ACROSS
 7. H_ ARMFUL = HARMFUL <causing injury>
 9. (.i)OTHER(a.) = OTHER <alternative>
10. <having key> TONAL = TO _N _A _L
11. IS DEE inside MD = MISDEED <wrong>
12. S TAR BOARD = STARBOARD <right on ship>
13. <drunk> SOT = SOOT, OO→O
14. <burned> LIT <books {literature}>
15. <pioneer> SPEARHEAD = SP + EA RHEA D
17. BOW* inside CELL = COWBELL <orchestra piece>
19. <woman perhaps> BIPED = BID outside PE
21. <quench> SLAKE = _S + LAKE
22. <new boy> STEPSON = (STEPS ON)

DOWN
 1. <sharpen> WHET = WET outside H
 2. <carry out> TRANSACT = TACT outside R ANS
 3. <postgrad> ALUMNA = MANUAL*
 4. ONSIDE R inside CABLE = CONSIDERABLE <important>
 5. S HOE = SHOE <Oxford, perhaps>
 6. <came before> PREDATED <went after>
 8. <did stall> FILIBUSTERED = (EDIBLE FRUITS)*
12. <faux pas> SOLECISM = SOLE CIS M
13. <embarrassed> SHEEPISH = SHE + PISH outside E
16. <recruit> ENLIST = _E_N _L_I_S _T
18. <sport> WEAR = W_ E_ A_ R_
20. _D ONE = DONE <finished>