Across:
1 Social outcast (PARIAH) turns up (= reverse indicator) covering head (hair = -RIAH) with top of anorak (top of ‘Anorak’ = -A-) entering prison (entering ‘Prison’ = P-) (PARIAH),
4 They’re plugged in (ADAPTORS) to Pastor (pastor) freely (= anagram indicator) (pastor = A-PTORS) welcoming State prosecutor (District Attorney = -DA) (ADAPTORS)
9 A loud (ORALLY) old (O-) marshal? (marshal/assemble = -RALLY) (ORALLY),
10 The line from the meteorologist’s office (ISOPLETH) is (IS-) – half (op) the creative work (half ‘OPus’ = -OP-) is left (-L-) to the (the) layout (= anagram indicator) (the = -ETH) (ISOPLETH),
12 The foreign (the = EL-) assets found at The Centre (‘asSEts’ found at the centre = -SE-) by women (-W-) present (-HERE) (ELSEWHERE) from a different place (ELSEWHERE),
13 Encourage (EGG ON) suits to leave suggestion (‘suits’ to leave ‘suggestion’ = ggeon = EGG ON),
14 It’s about (RE-) soldiers (GIs = -GIS-) getting a grip on the ground (traction) without getting caught (c) (‘traction without ‘c’ = TRATION) (REGISTRATION) identifying number on armoured vehicle? (REGISTRATION number),
18 Sounds like a lengthy queue in The Barracks (LONG DIVISION) for some of the tables (LONG DIVISION arithmetic tables),
21 Ally (UNITE) is out of line dropping fool (‘out of line’ dropping ‘fool’ = utine = UNITE).
22 They’re tied in a ropey way (REEF KNOTS) to underwriters, for instance (underwriter’s KNOT-), consumed by marine hazards (reefs = REEF -S) (REEF KNOTS),
24 Choose again to follow strategy (READOPTS) in disorganised (= anagram indicator) seaport (seaport = REA-OPTS) around Dublin (-D-) (READOPTS),
25 One of those in 23 down (‘knave’ = jack = playing CARD-) on one (-I-) area (-A) (CARDIA) in part of the stomach (CARDIA),
26 Brings up (= reverse indicator) retweet (RT = TR-) by model? (= anagram indicator) Crikey (crikey = -ICKERY) (TRICKERY) – you expect that from a magician! (TRICKERY),
27 Picks up (HEARS-) energy (-E) (HEARSE) – the type driving the dead (HEARSE).
Down:
1 Drugs (-EE-) in prison (prison) produced by (= anagram indicator) (prison = PION-RS) (PIONEERS) those who are unaffected by the bars presumably (those who don’t drink = PIONEERS),
2 Course (ROAD) for retiring (= reversal indicator) soldiers (GIs = SIG-) is not the first (‘Not’ the first = -N) (ROAD SIGN) offering direction to anyone going on a journey perhaps (ROAD SIGN),
3 Grant (ALLOW) in Cork (Mallow) needs no introduction (m) (‘Mallow’ without ‘m’ = ALLOW),
5 Madeira’s (Madeiras = DESSERT WINES) ports? (DESSERT WINES),
6 Season (PEPPER-) on (-ON-) island (-I) (PEPPERONI) goes down well with the Italians (PEPPERONI),
7 Looking over a cliff (ON EDGE) similar to 17 down? (‘in a state’ is similar to ON EDGE),
8 “What some doctors are capable of (spin doctors are capable of SP-IN-) around hospital (-H-) is wrong” (-X) – (SPHINX) the riddler of old (SPHINX / riddler),
11 Ridiculous (= anagram indicator) rate for (rate for = REF-ATOR) taking in doctor (-RIG-) from hospital ward (-ER-) (REFRIGERATOR) where one keeps the bodies in the mortuary (REFRIGERATOR),
15 The Masons are presumably proud of this (STONEWORK) Old Bob (old bob = shilling = S-), an old revolutionary (Theobald Wolfe Tone = -TONE-) joining Labour (labour = -WORK) (STONEWORK),
16 Detectives’ (DIs = DIS-) line-up (-ORDER) (DISORDER) for breach of the peace (DISORDER),
17 Popular (IN -) answer (A) and tweet (tweet/say = STATE) (IN A STATE) is edgy (IN A STATE),
19 Utter (utter) rubbish (= anagram indicator) (utter = TU-RET) about Romeo (-R-) (TURRET) in the tank top (TURRET on army tank),
20 Looking back (= reverse indicator), one (-I) law (law = -WAL-) for the papers (ID = DI-) (DIWALI) celebrated in India (DIWALI festival),
23 Jack (KNAVE) is one up from Number 10 (KNAVE = jack = 10 playing card).