ACROSS
 1. MO + R JAM outside OR = MARJORAM <herb>
 6. BUT_ outside EA = BEAUT <cracker>
 9. (DANCE IS NOT)* = SANCTIONED <permitted>
10. <determine age of> DATE <fruit tree>
11. <Brave heroine> MERIDA = ←A DIRE M←
12. (CITES OUR)* = OUTCRIES <protests>
13. <neighbour> ABUT = (A BUT)
15. IN D IS POSED = INDISPOSED <poorly>
17. (SOD + NAIVETY)* = VIDEO NASTY <controversial film>
19. "SIGHED" = SIDE <smaller serving>
20. <bear> SHOULDER = SHOULD _E _R
22. <beats in competitions> ONE-UPS = (US OPEN)*
24. <get ready> PREP = ←PER P←
25. <not moving> STOCK-STILL = STOCKS + TILL
26. D_ ITTY = DITTY <tune>
27. ←LAIR _O_ TUT← = TUTORIAL <lesson>

DOWN
 2. <peak performance> A game = (.t)AG AME(r.)
 3. K inside JACINTH (_EP_ _UL_) PIT = JACK-IN-THE-PULPIT <brown dragon>
 4. URINATION, ←R = RUINATION <downfall>
 5. A N_ H_ inside MOOD = MANHOOD <masculinity>
 6. <bathroom fixture> BIDET = BID E_ T
 7. (NETHERLANDS ROSE)* = ANDERSON SHELTER <wartime refuge>
 8. TIT + LEDE + ED = TITLE DEED <legal document>
14. BLITHE RED = BLITHERED <talked nonsense>
16. SKYR POCKET - P = SKYROCKET <mushroom>
18. <deal with> SORT OUT = "SORE TOUT"
21. <handsome> DISHY = DI SHY
23. P_O_ L_K_ A = POLKA <dance>