Across:
1 Type of business (‘Small to Medium-sized Enterprise = SME = S-ME) entertaining revolutionary (-CHE-) (SCHEME) plan (SCHEME),
4 Stirred up (AGITATED) in a State (AGITATED),
9 South-eastern European (BALKAN) outlaw (ban = B-AN) welcomes troop (walk) with no leader (w) (‘walk’ without ‘w’ = -ALK-) (BALKAN),
10 Any living thing (ORGANISM) with heart, for one (ORGAN-), is (-IS-) master (-M) (ORGANISM),
12 Previous one (previous/former one = ERSTWHILE) gets poor (= anagram indicator) rest (rest = ERST-) for some time (-WHILE) (ERSTWHILE),
13 Go off (SPOIL) to brief (y) agent (‘spy’ without ‘y’= SP-) for Texas tea (‘Texas tea’ = -OIL) (SPOIL),
14 A processor of images (GRAPHICS CARD) and artwork (GRAPHICS) for Queen (CARD) (GRAPHICS CARD),
18 Covers (BEDDING) for informer (PLANT) (BEDDING PLANT) incorporated in the plot (BEDDING PLANT),
21 Drink (RUM-) with couple starting to ballroom (couple/first two letters starting to ‘BAllroom’ = -BA) (RUMBA) dance (RUMBA),
22 Rob’s on the road (robs on the road = CARJACKER) with Jill’s partner (‘Jack and Jill’ = -JACK-) restrained by nurse (nurse = CAR-ER) (CARJACKER),
24 Endless (t) wine (‘port’ without ‘t’ = POR-) on weekend (‘weeK’ end = -K-) for college (-C-) dance (-HOP) (PORK CHOP) with the option of a meaty dinner (PORK CHOP),
25 Rugby player in the middle (CENTRE) of recent (recent) action (= anagram indicator) (recent = CENTRE),
26 Old pal (CRONY-) is (-IS-) master (-M) (CRONYISM) of giving out jobs for the boys (CRONYISM),
27 Godparents left out pots (‘godparents’ left out/without ‘pots’ = GARDEN) in cultivated ground (GARDEN).
Down:
1 Take a dive (SUBMERGE) for United (merged) shortly (d) (‘merged’ without ‘d’ = -MERGE) after (= position indicator) coming off the bench (substitute = SUB-) (SUBMERGE),
2 Course director (HELMSMAN) for pilot? (HELMSMAN),
3 Something Tom vocalised (MIAOW) to women (-W) has nothing (-O-) to do with objective (aim), in retrospect (= reversal indicator) (aim = MIA-) (MIAOW),
5 27 across (‘garden’ = GARDEN) finds 25 across (‘centre’ = CENTRE) (GARDEN CENTRE) is a source of inspiration for The Cherry Orchard, for example (GARDEN CENTRE),
6 Kit (kit = TEAM STRIP) is one of those in league (TEAM) with Peel (peel = STRIP) (TEAM STRIP),
7 Man of the cloth (TAILOR) showing off (= anagram indicator) Rialto (Rialto = TAILOR),
8 Hollow (DIMPLE) place (-PL-) in American capital (American capital/money = dime = DI-ME) (DIMPLE),
11 Comic (WIT-) from Switzerland (-CH) working in The Theatre (DOCTORS) (WITCH DOCTORS) with tribal magicians (WITCH DOCTORS),
15 Church leaders (HIERARCHY) greet (HI-) rare (rare = -ERAR-) review (= reversal indicator) that’s a fair bit (half of) touchy (half of ‘touCHY’ = -CHY) (HIERARCHY),
16 Offered for sale (MARKETED), butchers (= anagram indicator) red meat (red meat = MAR-ETED) over the weekend (‘weeK’ end = -K-) (MARKETED),
17 Endless (end ‘lesS’ = S-) time (-T-) to encourage (urge on = -URGEON) (STURGEON) one of those from school (STURGEON from school of fish),
19 Knocks back (= reversal indicator) wine (port = TROP-) from one (-I-) top cru (top ‘Cru’ = -C) (TROPIC) circling the globe (TROPIC),
20 Rome by (Rome by) train? (= anagram indicator) (Rome by = EMBYRO) That’s in the early stage of development! (EMBYRO),
23 Earn a (earn a) silly (= anagram indicator) (earn a = ARENA) reputation for showing off fighting skills and blood sports (ARENA).