Across:
8 Oscar (O-) is taken in by poet’s (poets = B-ARDS) (BOARDS) committees (BOARDS),
9 Has no energy (DEAD) for warm-up (HEAT) (DEAD HEAT) for track tie (DEAD HEAT),
10 Bear (‘Pooh’ Bear) up (= reversal indicator) (Pooh = HOOP) in the band? (band/ring = HOOP),
11 Every ounce of anger (ALL THE RAGE) in Vogue (in vogue = ALL THE RAGE),
12 Struggles (BRAWLS) with Bellow’s (bellows = B-AWLS) entertaining writing (from the 3Rs = -R-) (BRAWLS),
14 Jeer a mob (jeer a mob = JAMBOREE) travelling (= anagram indicator) to a large gathering (JAMBOREE),
15 Each partner (each and EVERY) is not (not = NO- -T) hovering around magician’s bar (wand = -W AND) – it’s for women’s party (-HEN) (EVERY NOW AND THEN) occasionally (EVERY NOW AND THEN),
18 Protection for Humpty Dumpty presumably (EGGSHELL) is a reflection of wall-to-wall cover? (EGGSHELL paint),
20 Scatter (= anagram indicator) mint (mint = M-TIN-) over top of unremarkable (top of ‘Unremarkable’ = -U-) yard (-Y) (MUTINY) – with the right force, it’ll take over (MUTINY),
22 A measure of the grades (REPORT CARD) of rumour (REPORT) coming from Number 10 (playing CARD) (REPORT CARD),
24 Celebrity (NAME) half of 17 down (half of ‘name drop’ = NAME),
25 Bill’s (bills = STATUTES) in Utah (-UT-) in America (America/ States = STAT-ES) (STATUTES),
26 A source of wisdom (ORACLE) covered up by advisor? A cleaner! (covered up by ‘advisOR A CLEaner’ = ORACLE).
Down:
1 Cool (cool = COLO-) jazz (= anagram indicator) from revolutionary (= reversal indicator) Russia (RU = -UR) (COLOUR) produced by shady type (COLOUR),
2 Release (DROP) the upsetting (= reversal indicator) extremes of police record (extremes of ‘POlice recoRD’ = pord = DROP),
3 Couple of beastly figures (ass + ass = ASSASS-) up (= reversal indicator) north (NI = -IN) (ASSASSIN) capable of getting away with murder (ASSASSIN),
4 Image (IDOL) is from part of Brunei dollar (part of ‘bruneI DOLlar’ = IDOL),
5 Measure the depth (FATHOM) and ample proportions (FAT-) for Trim (e) accommodation (home) (‘home’ without ‘e’ = -HOM) (FATHOM),
6 At the most (at the most = THE-MOSTAT), novel (= anagram indicator) includes writing (from the 3Rs = -R-) (THERMOSTAT) that runs hot and cold (THERMOSTAT),
7 Harry (annoy = nag) is after (= positional indicator) shortening (y) energy (‘energy’ without ‘y’ = energ) switch (= reverse indicator) (nag = GAN- + energ = -GRENE) (GANGRENE) – the type synonymous with circulation problems damaging the cells (GANGRENE),
13 Romantic poet (William WORDSWORTH) from The Script (WORDS-) is good value in the material sense (-WORTH) (WORDSWORTH),
14 It’s the crème de la crème (JEWEL) from one of The Stones (JEWEL),
16 Brief description (VIGNETTE) of engineer (= anagram indicator) vetting (vetting = VIGN-TTE) Oriental (East = -E-) inside (VIGNETTE),
17 Try to impress others with whom you know (NAME-DROP) produced big cheese (NAME-) from 2 down (‘drop’ = -DROP) (NAME-DROP),
19 Literary agent disregards a larger (‘literary agent’ disregards ‘a larger’ = iteynt = ENTITY) organisation (ENTITY),
21 Graceful on the ground (NIMBLE) with heads of mulberry bushes (heads of ‘Mulberry Bushes’ = -MB-) in flower (flower/river = NI-LE) (NIMBLE),
23 Nicholas drops chin (‘nicholas’ drops ‘chin’ = olas = ALSO) too (ALSO),
24 Type of spruce (NEAT) in Trim (NEAT).