Brilliant fun.
Thanks to Goliath for a fantastic puzzle. Witty, light and challenging in all the right ways.

ACROSS
1. Reform voters to be tried (6)
STROVE
4. Stay a while and feel part of the gang (6)
BELONG
8. Fashionable and lavish from a very young age (7)
INFANCY
IN (fashionable) + FANCY (lavish)
9. Obstacle race starts in 38 degrees? Always (7)
FOREVER
(O[bstacle] R[ace] (starts)) in FEVER (38 degrees?)
11. 9 originally ignored by oddly formal brotherhood (10)
FRATERNITY
[e]TERNITY (forever, from 9 across, originally ignored) by F[o]R[m]A[l] (oddly)
12. Country where money exchanges hands (4)
LAND
[r]AND (money) exchanges hands (i.e. switch R (right) for L (left))
13. Body temperature, roughly (5)
TORSO
T (temperature) + OR SO (roughly)
14. Discarded all clothing that’s pinstriped (8)
STRIPPED
Cryptic definition
P in STRIPED
16. One kneels for model (8)
PROPOSER
PRO (for) + POSER (model)
18. Soldiers like Goliath (5)
GIANT
20. Like father to come back without delay (4)
ASAP
AS (like) + PA< (father, <to come back)
21. Dealt with mail hacker impeccably (4,1,5)
LIKE A CHARM
(MAIL HACKER)* (*dealt with)
23. Great Tory leader slipped into prejudice (7)
BIGOTRY
BIG (great) + [T]ORY (leader slipped)
24. Shore drift contents end in nasty shock (7)
HORRIFY
[s]HOR[e] [d]RIF[t] (contents) + [nast]Y (end in)
25. Sex with a tiny drop of dressing in green salad (6)
GENDER
D[ressing] (tiny drop of) in GREEN* (*salad)
26. Next door starting to get into beer for a heavy boozing session (6)
BENDER
(N[ext] D[oor] (starting)) to get into BEER
DOWN
1. This helps chart cycling crime (5)
SONAR
2. Perhaps nuclear to some, God’s beginning to drop (7)
REACTOR
[c]REATOR (God, beginning to drop)
3. Central Park outwardly nasty as experienced by others (9)
VICARIOUS
[p]AR[k] (central); outwardly VICIOUS (nasty)
5. Wood finally wore thin (5)
EBONY
[wor]E (finally) + BONY (thin)
6. Done with friend returning to share space (7)
OVERLAP
OVER (done) with PAL< (friend, <returning)
7. Countryside award for martial arts (5,4)
GREEN BELT
10. Broadcasts three-wheeler attack (3,6)
AIR STRIKE
AIRS (broadcasts) + TRIKE (three-wheeler)
13. Item covering ill-considered defeat (9)
THRASHING
THING (item) covering RASH (ill-considered)
15. Nonsense part below a grim layout (9)
RIGMAROLE
ROLE (part) below (A GRIM)* (*layout)
17. Police officer in shoddy finale of action film spoiler? (7)
POPCORN
PC (police officer, police constable) in POOR (shoddy) + [actio]N (finale of)
19. Total, including present, getting stuck (7)
ADHERED
ADD (total) including HERE (present)
21. Substantial contribution to molecular genetics (5)
LARGE
[molecu]LAR GE[netics] (contribution to)
22. Allude one way or the other (5)
REFER
Cryptic definition
‘One way or another’ tells us we need a palindrome
Very versatile, crafty, witty, and dare I use the word, Goldilocks.
As Oriel rightly observes, challenging, but in all the right ways. There’s a “pay-off” in every clue, it’s simply a gem of a puzzle.
My cap is skyward, big thanks, big man & Oriel
You summed it up nicely, Oriel. Very enjoyable, indeed. I ticked LIKE A CHARM, VICARIOUS, INFANCY for their surfaces, and thought FOREVER and ARSON were both clever.
All parsed and no questions, although It did take me a while to see how STRIPPED worked.
Thanks Goliath and Oriel
Thanks for the blog , brilliant as always . STRIPPED is so clever with the rare double fission and so many other neat clues . LIKE A CHARM could have mentioned quarks .
For REACTOR I had the “to some” bit going with God .
Very enjoyable. See, it’s possible to compile a great puzzle with no obscurities. STRIPPED was the only one I didn’t parse.
There is nothing at all that I can add to Oriel’s preamble and others’ comments above.
A gem of a puzzle indeed and a superb blog – huge thanks to both.
Such a pleasure to solve. Thanks.
Agree with all of the above. Goliath remains a firm favourite of mine especially on this performance.
STRIPPED, INFANCY, FOREVER and the grid’s bottom row all earned ticks.
Many thanks to both.
What Geoff Down Under #4 said.
14ac: I know a lot of people like this device, but it leaves a crucial step of the operation unclued. Would it not have been even more clever to write something like “Torn pinstriped clothing discarded”? This gives “Torn” as the indication to convert “pinstriped” into “p in striped”.
Thanks Goliath for the rest of the puzzle and Oriel for the blog.
2dn: Same as Roz@3, I had “to some, God” as indicating CREATOR.
Maybe my fastest full cryptic solve of the year, but I agree with everyone else that this was a delight and there was certainly some intrigue along the way.
Diane @7 referred to the bottom row, i.e. GENDER BENDER. Looking around the grid (FRATERNITY, STROVE, BELONG, STRIPPED TORSO, BIGOTRY, HORRIFY) it feels like there’s some kind of theme here, but nothing that’s obviously specific to me.
Great puzzle anyway, thanks GOLIATH and Oriel.
Very enjoyable and no ghastly TALMA-like clue (from yesterday) to spoil the fun.