Thank you to Budmo. Definitions are underlined in the clues.
Across
1. Tour boring little American shopping centre (5,4)
STRIP MALL : TRIP(a tour/journey) contained in(boring) SMALL(little).

6. University official cut right-hand page (5)
RECTO : “rector”(the highest-ranking academic officer of a university) minus its last letter(cut).
Defn: …, as seen in an open book that is read from left to right.
9. Cryptic clue originally rejected for sore (5)
ULCER : Anagram of(Cryptic) CLUE + 1st letter of(originally) “rejected”.
10. Stimulate a Svengali to change (9)
GALVANISE : Anagram of(… to change) A SVENGALI.
Defn: …/spur into action.
11. Relish rise in value (10)
APPRECIATE : Double defn: 1st: To recognise the good quality, worth or significance of someone or something.
12. Frustrate – bother! (4)
DASH : Double defn: 1st: To prevent something from happening, eg. one’s hopes; and 2nd: Like “Bother!”, an expression of annoyance.
14. Bit of tame excuse for betraying one’s country (7)
TREASON : 1st letter of(Bit of) “tame” + REASON(an explanation/excuse for something done).
15. It is beginning to trigger southern bigots (7)
SEXISTS : SEX(a euphemism for which is “it”) + IS + 1st letter of(beginning to) “trigger” + S(abbrev. for “southern”).
17. Accomplishments of leaderless rebellious groups (7)
ACTIONS : “factions”(distinct groups, within a bigger group, that are rebellious in having different ideas, beliefs or goals from those in the latter) minus its 1st letter(leaderless …).
19. Inadequate, periodically knelt in school yard (7)
SKETCHY : 1st, 3rd and 5th letters of(periodically) “knelt” contained in(in) [ SCH(abbrev. for “school”) + Y(abbrev. for “yard”, a unit of measurement of distance) ].
20. Fifty in total hovel (4)
SLUM : L(Roman numeral for “fifty”) contained in(in) SUM(total).
22. Piano part I played in Spectre (10)
APPARITION : Anagram of(… played) PIANO PART I.
25. Persuade retinue to replace Tesla with Cadillac at last (9)
ENCOURAGE : “entourage”(a group of assistants, servants or friends that travel with an important person) replacing(to replace) “t”(abbrev. for “Tesla”, unit of magnetic flux density in physics) with last letter of(with … at last) “Cadillac”.
26. Prelude from Fortnite rejected (5)
INTRO : Hidden in(from) reversal of(… rejected) “Fortnite”.
Defn: The first part of, say, a piece of music.
27. Flower close to ornament, unwanted plant (5)
TWEED : Last letter of(close to) “ornament” + WEED(an unwanted plant growth, say, in the garden).
Defn: … or something that flows, like a river, in this case one in South East Scotland and North East England.
28. One blocking weapons regulation (9)
ORDINANCE : I(Roman numeral for “one”) contained in(blocking) ORDNANCE(military supplies, including weapons).
Down
1. Son on Caribbean island getting breathing apparatus (5)
SCUBA : S(abbrev. for “son”) plus(on) CUBA(Caribbean island).

2. Beneficiary of surprisingly nice trip around Spain (9)
RECIPIENT : Anagram of(surprisingly) NICE TRIP containing(around) E(the International Vehicle Registration code for Spain).
3. A model’s abnormal sexual desire (10)
PERVERSION : PER(each/a) + VERSION(a particular distinct form/a model of something).
4. German Christian snubbing Charlie (7)
ANGLIAN : “Anglican”(a member of the Church of England) minus(snubbing) C(letter represented by “Charlie” in the phonetic alphabet).
Defn: As an adjective, refering to the Angles, a Germanic tribe, and as a noun, a member of the Angles.
5. Overdue entering records? They must be displayed before passing (1-6)
L-PLATES : LATE(overdue/past the specified time) contained in(entering) LPS(audio recording formats in the form of discs/records).
Defn: … a driving test.

6. Study sound made by grass (4)
READ : Homophone of(sound made by) “reed”(tall slender plant growth found in swamps and shallow waters/grass).
Defn: To … a specific academic subject at university level.
7. Tea bags popular for teacups? (5)
CHINA : CHA(tea) containing(bags) IN(in fashion/popular).
Defn: Ceramic ware, including ….
8. Dreadful toy shaver produces rash (9)
OVERHASTY : Anagram of(Dreadful) TOY SHAVER.
Defn: …/reckless.
13. Voyage in haste (10)
EXPEDITION : Double defn: 1st: An organised journey/… for a particular purpose; and 2nd: …/swiftness.
14. Passing agnostic oddly bathed in Midlands river (9)
TRANSIENT : 1st, 3rd, 5th and 7th letters of(… oddly) “agnostic” contained in(bathed) TRENT(river in the Midlands of England).
Defn: …/of a temporary nature.
16. South American footballer Ronaldo mostly ignoring current church official (9)
SACRISTAN : S(abbrev. for “South”) + A(abbrev. for “American”) + “Cristiano”(Ronaldo, Portuguese footballer) minus its last letter(mostly) minus(ignoring) “i”(symbol for electric current in physics).
18. Soon upset with rap singer (7)
SOPRANO : Anagram of(… upset …) [SOON plus(with) RAP ].
19. Observe we had picked up marine algae (7)
SEAWEED : Homophone of(… picked up) [ “see”(to observe/look) + “we’d”(contraction of “we had”) ].
Examples:
21. Article taken away from dirty relative (5)
UNCLE : “an”(article in grammar) deleted from(taken away from) “unclean”(dirty).
23. Not a soul expected, initially, after midday (2,3)
NO ONE : 1st letter of(…, initially) “expected” placed below(after, in a down clue) NOON(midday).
24. Kitty’s enjoyable day (4)
FUND : FUN(enjoyable/entertaining) + D(abbrev. for “day”).
Defn: …/a shared pool of money.
Some balm for those mourning the loss of the Independent crossword as Eccles appears as Budmo. Lovely smooth surfaces.
Very enjoyable. Favourites were SEXISTS, PERVERSION and CHINA.
Ta Budmo & scchua.
SACRISTAN is clever as well, as the other Ronaldo is indeed a South American from Brazil.
I couldn’t parse 7d – haha, very clever!
New for me: STRIP MALL, SACRISTAN.
I hadn’t heard of SACRISTAN, nor the footballer. Otherwise all fell into place and was enjoyed.
Thanks for the blog, scchua.
I was trying to parse SEXISTS as:
“it is” = EXISTS, plus S for “southern” – and couldn’t figure out what purpose “trigger” had…
“It” is such an outmoded word for sex that I clean overlooked it. Hey ho.
I thought ORDINANCE was particularly neat.
12ac is actually a triple definition, because there is a dash in the clue: Frustrate – bother!
Lovely after yesterday’s non-QC and the car crash that was my encounter with Paul on Friday.
Wellbeck @6 I liked ordinance too. It was also a blast from the past, because there was an Ordnance Road round the corner from where I lived as a child. Loads of people called it “Audience Road” and so I (precocious little horror that I was) looked up “ordnance” in the dictionary and started correcting them.
Wow thought this was quite tough for a Quiptic!
I thought it was quite easy at first, but with a few tough little nuggets lurking among the soft centres: SACRISTAN held me up because I didn’t know the footballer, and GALVANISE, SEXISTS and ANGLICAN took their time.
Thanks Budmo and scchua. I thought PERVERSION was particularly smooth.
Has Saturday finally come?
Fun crossword. I’m quite impressed that ⅙ of commenters preceding me hadn’t heard of one of the most famous people on the planet. The world’s changed since the most famous names were known to everyone.
Thanks Budmo and scchua.
Thanks Budmo and scchua.
A tricky one but a walk in the park compared to yesterday’s quick cryptic. My favourite was ‘sacrostan’ aided by constant football discussions in my household. The downs were much easier once the crossers were in place.
Third use of ‘it’ = sex this week. Sigh. Otherwise good fun.
A few words I’d never heard of. My excuse is that I studied Physics (a long time ago), not Humanities. Didn’t stop me wondering what Mr Musk’s car was doing in 25 mind.
I found that quite hard but got through it eventually. Last one in was PERVERSION. I really struggled with a = per and that threw off my attempt to deal with the rest of the clue.
Good fun, lots to like. ‘Nuff said 🙂
Thanks Budmo and Scchua. Middling for me, and found it easier than yesterday’s Quick cryptic. RECTO was new for me, but one I suspect is a good one to kmow for crossword land. Some great surfaces in there.
Posting from the UK on Sunday instead of my usual Monday USA time…
I gave up on DASH. Should have got it, but I’ll blame jet lag, so hit reveal.
Otherwise smooth sailing. Ta, both!
At 15a I chased the same red herring as Wellbeck @6, at a loss regarding the seemingly redundant T clue and the extra S in the solution. (Not a fan of “It” either, especially when it refers to SEX itself—as opposed to glamour or allure, which clues in the opposite direction often do.) Otherwise I found it pretty smooth going, with a few parsings arriving via tea-tray following a guess.
I’ll register a small quibble about “German” with the meaning ‘Germanic’ because, from a modern perspective at least, (Old) English is the latter but not the former. No obstacle to getting the solution, though.
NHO the name for L-PLATES, but having some confidence in my 1a solution I made the leap from the cluing trope of _learner_ for L to the definition.