Across:
1 On reflection (= reversal indicator), fire (fire) half of (half of “fire” = re = -ER) tavern (pub = BU-P-) over opening moonshine (opening “moonshine” = -M-) (BUMPER) for the young horsey types (BUMPER race),
4 One- (I-) -third of gamblers (third of “gamblers”= -M-) run off (-PRINT-) with the last of the winnings (last of the “winnings” = -S) (IMPRINTS) from bookmakers (IMPRINTS),
9 Russell (AE-) reviewed (= reversal indicator) Room for that beasty lot (lair = -RIAL) (AERIAL) on the radio (AERIAL),
10 Lively type (ANIMATED) made it an (made it an = ANIMATED) order (= anagram indicator),
12 Have contact with (TOUCH-) court (-WOO-) judge at the centre (“judge” – at the centre = -D) (TOUCHWOOD) of Tinder – that will ignite things (tinder/flammable wood = TOUCHWOOD),
13 Strength of character (NERVE) is never (never = NERVE) wrong (= anagram indicator),
14 Agitate (FERMENT-) for empire (nation) to get rid of leader (n) (“nation” without “n” = -ATION) (FERMENTATION) – if that happens we’ll have a drink (FERMENTATION),
18 Part of social group (LOWER CLASSES) during the early years at the national school (LOWER CLASSES),
21 Wax lyrically (ORATE) to old (O-) judge (-RATE) (ORATE),
22 The fast ways (SHORTCUTS) of the skinheads? (SHORTCUTS),
24 Worships images (IDOLATER) of tailored (tailored = IDOLATER) dress (= anagram indicator),
25 Meat in (meat in = INMATE) stew (= anagram indicator) could be from an American can locally? (from American “can” / jail = INMATE),
26 Loud music (forte = -F-) at a foreign (a = -EIN-) restaurant (CAF-E) outside (CAFFEINE) will keep you awake at night (CAFFEINE),
27 Roman emperor (Nero = OR-EN-) retires (= reversal indicator) around island (-I-) near Troy (-T) (ORIENT) in the East (ORIENT).
Down:
1 Damn (BLAST-) sour type (-OFF) (BLAST-OFF) shouts it out at the end of Countdown! (BLAST-OFF),
2 Army tour (army tour = MORTUARY) out of place (= anagram indicator) in the dead zone temporarily (MORTUARY),
3 Chase (chase = ECASH) criminal (= anagram indicator) with cryptocurrency (eCash = ECASH),
5 Shaft (MINE) one of those exposing smokers (smoke DETECTOR) (MINE DETECTOR) – one senses there might be charges in a way (MINE DETECTOR),
6 Caesar, for one (ROMAN), got (got = TOG-) served up (= reversal indicator) a (-A) (ROMAN TOGA) type of Italian wrap (ROMAN TOGA),
7 Get around without dog (“get around” without “dog” = etarun = NATURE) in the countryside (NATURE),
8 Endless (s) American beer (“suds” without “s” = SUD-) for The Lions (-DEN) (SUDDEN) is unexpected (SUDDEN),
11 One Direction (SOUTH-EASTERN) in old European capital (old French capital/money coin = SOU- coin) provides the (the = -TH-E-) backing for The Waterboys? (back of a ship = -ASTERN) (SOUTH-EASTERN),
15 Former (EX-) revolutionary leader (Tone) loses head (T) (“Tone” without “T” = -ONE-) with most of (o) 21 across (“orate” without “o” = -RATE) (EXONERATE) – is that clear to the court? (EXONERATE),
16 Funny, that’s rather a lovely touch (funny/humorous type of kiss = OSCULATE) offering clues to a (clues to a = OSCULATE) puzzle (= anagram indicator),
17 In my opinion (AS I SEE IT), other spies can’t get their heads around my view (AS I SEE IT),
19 Sets-up (= reversal indicator) firm (Co = O-C) incorporating assistance (aid = -DIA-) from foundation in Biarritz (foundation in “Biarritz” = Z-) (ZODIAC) for those making predictions (ZODIAC),
20 Left (l) out of deciding game (“play off” without “l” = PAY OFF) as a bribe (PAY-OFF),
23 Piano technician (TUNER) is on the radio (TUNER).