Across:
8 Layperson has no son (‘layperson’ has no ‘son’ = layper = PLAYER) working in the abbey (working in The Abbey Theatre = PLAYER),
9 Greek character (22nd character of Greek alphabet = -CHI) following (= position indicator) woman (MARIA-) (MARIACHI) in group of strolling musicians (MARIACHI),
10 Contemplates (muses) cutting 1000 (m) (‘muses’ without ‘m’ = USES) functions (USES),
11 Harry (harry/harass = DOG) from Nice (Nice BISCUIT) (DOG BISCUIT) provides a treat your setter (dog) appreciates (DOG BISCUIT),
12 Is not slow (PROMPT) to offer a few lines to struggling actor (PROMPT),
14 Set (set) play (= anagram indicator) (set = EST-) from one (-I-) friend (-MATE) (ESTIMATE) – a ballpark figure (ESTIMATE),
15 Most of those (s) in 25 across (‘forwards’ without ‘s’ = FORWARD-) dreaming about (= - THINKING) (FORWARD-THINKING) what’s involved in fortune telling (FORWARD-THINKING),
18 A line from unsentimental (‘a line’ from ‘unsentimental’ = unstment = STUNTMEN) risk takers in a film (STUNTMEN),
20 Arrangement (FORMAT) for class (FORM-) act heading (‘Act’ heading = -A-) for Top Ten (top ‘Ten’ = -T) (FORMAT),
22 Numerous infections (disorders/ailments = CONDITIONS) in state (CONDITION-) school (-S) (CONDITIONS),
24 Partnership (TEAM) to curate a museum’s content (‘curaTE A Museums’ content = TEAM),
25 Rugby players (FORWARDS) shameless (FORWARD-) at first scrum (first ‘ Scrum’ = -S) (FORWARDS),
26 Deliberating avoid using (ESCHEW) drugs (E-) with barman (Senior Counsel = -SC-) and hack (-HEW) (ESCHEW).
Down:
1 Stuffier (CLOSER), cold (C-) and may be sore (sore -LOSER) (CLOSER),
2 The Observer’s (the observers = EYES) content recalled (= reverse indicator) by Jersey entrepreneur (content recalled by ‘jerSEY Entrepreneur’ = seye = EYES),
3 Director (director) working (= anagram indicator) (director = CREDITOR) with at least one of them in accounts (CREDITOR),
4 Groomsman dumps Norma (‘groomsman’ dumps ‘Norma’ = goms = SMOG) in a haze that pollutes the atmosphere (SMOG),
5 A (A-) retweet (-RT-) is (-IS-) close to racist (close/end to ‘racisT’ = -T) (ARTIST) from one creating a scene (ARTIST),
6 Maguire and Paterson (match maker = MATCHMAKER) working at Lisdoonvarna festival (MATCHMAKER),
7 Name in a church (CHRISTEN), college (C-) building (= anagram indicator), shrine (shrine = -HRIS-EN) over time (-T-) (CHRISTEN),
13 Cutting of grass (MOWING) for The Blues (DOWN) (MOWING DOWN) leads to shooting that comes in bursts that’s deadly (MOWING DOWN),
14 Taken in (EATEN) by Eton (Eton) speech (= homophone indicator) (“Eton” = “EATEN”),
16 Conventional (ORTHODOX) alternative (OR-) to hot (hot), wild (= anagram indicator) (hot = -THO-) party (-DO-) for mystery man (-X) (ORTHODOX),
17 Popular (IN-) street (-ST-) covered with fodder (feed = -FE-ED) (INFESTED) crawling with rats (INFESTED),
19 Grown up (MATURE) friend (mate = MAT-E) taking in old city (-UR-) (MATURE),
21 Wipe the sleep from eyes (AWAKEN), as water snake is not taking rest (‘water snake’ is not taking ‘rest’ = wanake = AWAKEN),
23 Put out (OUST) by what’s apparent in nervous tissue (what’s apparent in ‘nervOUS Tissue’ = OUST),
24 Sample of Robusta coffee (sample of ‘robusTA COffee’ = TACO) served up in Mexican restaurant (TACO).