Across:
8 Is getting out of Carlisle (‘is’ getting out of ‘Carlisle’ = carlle = CELLAR) for a basement in Bordeaux (CELLAR),
9 Awful (= anagram indicator) crush (crush = CHUR-S) over revolutionary (-CHE-) (CHURCHES) types synonymous with a form of worshiping (CHURCHES),
10 Mentor leaves tournament (‘mentor’ leaves ‘tournament’ = tuna = TUNA) with one of the swimmers (TUNA),
11 Spartan (GREEK) handy gear (gloves /“mitts” = “myths” = MYTHS) reportedly (= homophone indicator) (GREEK MYTHS) tells you a lot about Amazon and the Midas touch (GREEK MYTHS tell you a lot about legendary Amazon and the Midas touch in Greek mythology),
12 Political leader (“political” leader = P-) gets pay (pay = -AP-Y-) off (= anagram indicator) accommodating American (-A-) – a (-A) (PAPAYA) bit of a smoothie perhaps (PAPAYA),
14 The foreign (the = EL-) wild (= anagram indicator) quote (quote = -OQUE-T) about Nationalist leader (‘nationalist’ leader = -N-) (ELOQUENT) is persuasive (ELOQUENT),
15 The odds on Hamlet’s dead father getting back his crown (A GHOST OF A CHANCE) – bet that’s a slim possibility (A GHOST OF A CHANCE),
18 Central American (HONDURAN) union leader (‘union’ leader = -U-) after (= positional indicator) heartless (u) cur (‘hound’ without ‘u’ = HOND-) sought office (-RAN) (HONDURAN),
20 Provoke (NEEDLE) elder statesmen to get rid of the smart set (‘elder statesmen’ to get rid of the ‘smart set’ = eldeen = NEEDLE),
22 Where John ended up when he lost the head (John the Baptist’s head ended up ON A PLATTER) – you’ll get this with little or no effort (ON A PLATTER),
24 Performs a role (ACTS) in Cast- (cast = ACTS) -away? (= anagram indicator),
25 They take over illegally (USURPERS) playing (= anagram indicator) Super (super = -SURPE-) Reds first (‘reds’ first = -R-) in America (U-S) (USURPERS),
26 I (“I” = “eye” = EYE-) heard (= homophone indicator) cover (-LID) (EYELID) is affected by the chap who brings the sand (EYELID closed by ‘the sandman’ for sleep).
Down:
1 That’s one in the eye (NEBULA in the cornea) for The Cloud (NEBULA),
2 Run off (“flee” = “FLEA”) report (= homophone indicator) by one of those associated with The Plague (FLEA),
3 One can boast (BRAGGART) spoilt kid (BRA-T) caught grand (G-) fish (-GAR-) (BRAGGART),
4 Spots (ACNE) bottle of Armagnac nevertheless (bottle of ‘Armagnac nevertheless’ = ACNE),
5 It’s a strange bird (weird/strange = CUCKOO = bird) who only makes an appearance at certain times (CUCKOO in a cuckoo clock),
6 Pretend (ACT) you (YOU-) have a temper (rage = -R AGE) (ACT YOUR AGE) – is that responsible advice from your mother? (ACT YOUR AGE),
7 Engineer (MECHANIC) of church (-CH-) involved in cinema (cinema = ME-ANIC) complex (= anagram indicator) (MECHANIC),
13 Doesn’t mind losing (A GOOD SPORT) American (A) going with half of 16 down (half of ‘goodness’ = GOOD) for endless (end ‘less’ = S-) drink (-PORT) (A GOOD SPORT),
14 Female (-F-) in river (Nile) swimming backwards (= reversal indicator) (Nile = EL-IN) (ELFIN) can be rather delicate (ELFIN),
16 Criminal (= anagram indicator) goes on (goes on = GOO-NE-S) about DS? (-D-S-) (GOODNESS) Wow! (GOODNESS),
17 They’re found technically in Spain (islands / the CANARIES) in Caesar (in Caesar = CANARIES) dressing (= anagram indicator),
19 Put off departure (‘put’ off ‘departure’ = dearre = READER) from the library (READER),
21 Pull out all the stops (LET RIP) in triple (triple = LET RIP) jump (= anagram indicator),
23 Caretakers with no career (‘caretakers’ with no ‘career’ = taks = TASK) or something to do (TASK),
24 Some postage stamps (some ‘postage stamps’ = AGES) from the Belle époque and the Fin de Siècle (AGES).