Across:
8 Be serious (be serious! = COME ON!) with firm (CO-) with workers (men = -ME -N) around Ring (O-) (COME ON),
9 One on board (DIRECTOR) closing 15 across (closing ‘funeral director’ = DIRECTOR),
10 Stimulant (SPUR) found on both sides of revolting (= reverse indicator) rubbish dumps (both sides of revolting ‘RUbbish dumPS’ = rups = SPUR)
11 Where you might find picture (IN THE FRAME) under consideration (IN THE FRAME),
12 Aston Martin (CAR-) taken by Bond (bond) – almost (d) (‘bond’ without ‘d’ = -BON) (CARBON) the typical dating material? (CARBON dating),
14 Doing the rounds ad nauseam (doing the rounds ‘Ad nauseaM’ = AM-) on outcome (-ENDING) (AMENDING) by making changes (AMENDING),
15 Most of those from 25 across (most of ‘funerals’ = FUNERAL) employed by a movie studio (DIRECTOR) (FUNERAL DIRECTOR) – the one undertaking to commemorate The Dead (FUNERAL DIRECTOR),
18 A lazy type (SLUGGARD) of Yank (yank = drag) knocks back (= reverse indicator) (drag = -GARD) local drink (SLUG-) from the start (= position indicator) (SLUGGARD),
20 Tries a (tries a) novel (= anagram indicator) (tries a = SATIRE), a parody of others (SATIRE),
22 Small (S-) part of sentence (-WORD) at engagement (FIGHT) (SWORD FIGHT) for those doing the fencing (SWORD FIGHT),
24 Sobers up without Rose (‘sobers up’ without ‘Rose’ = bsup = PUBS) in a number of bars (PUBS),
25 Pig from Persian Gulf (‘pig’ from ‘Persian Gulf’ = FUNERALS) witnessed in grave circumstances (FUNERALS),
26 Allow (LET) letters associated with 25 across (RIP = letters associated with ‘funerals’) (LET RIP) to deliver a tirade (LET RIP).
Down:
1 Local criminal (hood) isn’t finished (d) (‘hood’ without ‘d’ = HOO-) putting pressure (-P-) on American city (-LA) (HOOPLA) producing unnecessary fuss (HOOPLA),
2 Clear the air without Charlie (‘clear the air’ without ‘Charlie’ = etar = TEAR) – RIP (rip/slash = TEAR),
3 One (I-) barber’s pole (-SIGN-) in Ulster (-N-I-) is a (-A) (INSIGNIA) badge of honour (INSIGNIA),
4 Some get ideas back to front (= reverse indicator) (some ‘geT IDEas’ = tide = EDIT) and change their story? (EDIT),
5 Ain’t deserting great-niece (‘aint’ deserting ‘greatniece’ = Greece = GREECE) in the union (GREECE is in the European Union),
6 Damage (SCAR-) and ugly (= anagram indicator) decay (decay = -EDY-CA-) on front teeth (front ‘Teeth’ = -T) (SCAREDY-CAT) – presumably, this is why one is afraid to go to the dentist? (SCAREDY-CAT),
7 College (C-) at the end of term (end of ‘terM’ = -M-) in Arabian country (Oman = -OM-AN-) has party (-DO) (COMMANDO) for one going on The Missions (COMMANDO),
13 For those not in The House, who want a cigarette (BEER GARDEN) or drink (BEER), it’s a growing concern (GARDEN) (BEER GARDEN),
14 A (A-) theologian (Doctor of Divinity = -DD-) and writer (-ED) (ADDED) went on to say something more (ADDED),
16 Is not just (UNLAWFUL) permitted (-LAWFUL) following (= position indicator) star (sun) without an introduction (s) (‘sun’ without ‘s’ = UN-) (UNLAWFUL),
17 Transplant (RESETTLE) to let trees (let trees) develop (= anagram indicator) (let trees = RESETTLE),
19 A (A-) party (Fianna Fáil = -FF-) in Wicklow (Bray) getting rid of leader (b) (‘Bray’ without ‘b’ = -RAY) (AFFRAY) from Donnybrook (AFFRAY),
21 Religious leader (RABBI-) has a bone to pick (-T bone) (RABBIT) in The Warren perhaps (RABBIT),
23 Type of mustard (mustard GAS-) pot opened (‘Pot’ opened = -P) (GASP) with one big blow (GASP),
24 The way to go (PATH) to develop a thought, in part (‘develoP A THought’ in part = path = PATH).