Across:
1 Rave about (PRAISE) power (P-) similar to 13 across (‘hoist’ is similar to -RAISE) (PRAISE),
4 Doesn’t show (OBSCURES) up (= reverse indicator) the stink created by individual (Body Odour = BO = OB-) getting top-secret (top ‘Secret’ = -S-) treatments (-CURES) (OBSCURES),
9 Take a job with a major employer (join army = ENLIST) by inlet (inlet) out (= anagram indicator) (inlet = ENLI-T) around Point (South = -S-) (ENLIST),
10 What goes around (ROTATION) comes around? (ROTATION),
12 Dismissing someone (LETTING GO) is a worry for the parents when it comes to this issue (LETTING GO of their children/issue),
13 Jack up (HOIST) price abandoning this copier (‘price’ abandoning/leaving ‘this copier’ = thiso = HOIST),
14 Stagecoach (stagecoach = DILIGENCE) is outstanding (DUE) from the start (= position indicator) (DUE DILIGENCE) and that’s a concern for anyone doing preparatory work on Wall Street (DUE DILIGENCE),
18 What the whistle-blower is capable of (DENUNCIATION) is informing (DENUNCIATION),
21 Some upsetting (= reverse indicator) nightmare possibly (some ‘nightmARE POssibly’ = arepo = OPERA) in Ring, for one (Ring OPERA),
22 Give lessons (teach = T-EACH) covering tips, advice, opinions, ideas, suggestions (tips ‘Advice Opinions Ideas Suggestions’ = -AOIS-) (TAOISEACH) for a job in the house (TAOISEACH),
24 Sport (= anagram indicator) ran by duo (ran by duo = BOUNDARY) a big hit with the cricketers (a BOUNDARY = four runs in cricket),
25 Look for someone (SEARCH) to reach (reach) out (= anagram indicator) (reach = -EARCH) to after (= position indicator) school (-S) (SEARCH),
26 Tennis player refuses naps (‘tennis player’ refuses ‘naps’ = tenilyer = ENTIRELY) altogether (ENTIRELY),
27 A (A-) small (-S-) flower (River -LEE-) that’s soft (soft/piano = -P) (ASLEEP) and dormant (ASLEEP).
Down:
1 Bar (PRECLUDE) in park (P-) is about (-RE-) to introduce drinks (introduce ‘Drinks’ = -D-) in guide that appeals to cruciverbalists (clue = -CLU-E) (PRECLUDE),
2 Gave out (ALLOTTED) in a (A-) couple of lines (-LL-) to over-the-top (-OTT-) writer (-ED) (ALLOTTED),
3 Brush aside leaving bread (‘brush aside’ leaving ‘bread’ = ushsi = SUSHI) that’s served in Japanese restaurant (SUSHI),
5 See Red (BLOW ONE’S COOL) get angry (BLOW ONE’S COOL),
6 Clips (clips/cuts ‘t’) of three gossips (gossip x 3) (‘chat + chat + chat without ‘t ‘ = CHA-CHA-CHA) from tea dance? (cha/tea dance = CHA-CHA-CHA),
7 Fruity snack (RAISIN) for short (e) hike (‘raise’ without ‘e’ = RAIS-) up (= reversal indicator) north (NI = -IN) (RAISIN),
8 Immersed in Coup D’état, a nostalgic (immersed in ‘coup détAT A NOStalgic’ = atanos) revolutionary (= reversal indicator) (atanos = SONATA) series of movements (SONATA)
11 Riga cultural (Riga cultural) organisation (= anagram indicator) (Riga cultural = AGRICULTURAL) is not urban in its outlook (AGRICULTURAL),
15 European (ICELANDER) cleared in (cleared in) mix-up (= anagram indicator) (cleared in = ICELANDER),
16 Detectives (detectives = DIs = DIS-) work out (-AGREE) (DISAGREE) how to cross Swords (cross swords = DISAGREE),
17 Caught unprepared perhaps (ON THE HOP) avoiding the other classy types locally? (play truant ‘locally’ = on the mitch / ON THE HOP),
19 Welfare payment (DO-LE) covers pub (pub) that doesn’t open (p) (“pub” without “p” = -UB-) (DOUBLE) for drink (DOUBLE),
20 By-product (RESULT) of Ulster (Ulster) Question? (= anagram indicator) (Ulster = RESULT),
23 Moves (STEPS) by spymaster releasing army (‘spymaster’ releasing ‘army’ = spste = STEPS).