ACROSS
 9. <rival> ARCHENEMY = ARMY outside HENCE*
10. <country estate> VILLA = ←(.i)AL LIV(e.)←
11. BOTH outside _R = BROTH <soup>
12. (TRIES ON)* outside PO = ROSE-POINT <patterned lace>
13. <disqualified> OUT = _O_ _U_ + T_
14. OFF ICER'S HIP = OFFICERSHIP <position of authority>
17. CRUEL* outside K I = LUCKIER <with greater fortune>
19. <excavation site> SANDPIT = (.l)S AND PIT(c.)
21. <reconsiders value> REAPPRAISES = REAP PRAISES
24. N after IN = INN <lodginghouse>
25. <like Henry VIII's first wife> ARAGONESE = ARSE outside AG ONE
27. <what the Colosseum was> ARENA = ←AN ERA←
28. CR I'M E = CRIME <breaking the rules>
29. _S _U_L _T _A_N _A_ T_E_ = SULTANATE <monarch's role>

DOWN
 1. <trickster> BAMBOOZLER = ←MAB← + _L inside BOOZER
 2. SOCRATIC* = ACROSTIC <poetic form>
 3. T + N inside ECHO = TECHNO <type of dance>
 4. <dry land> TERRA FIRMA = _T FARRIER* MA
 5. <they're basic> LYES = "LIES"
 6. ←AVE← + PER ON = EVA PERON <Madonna part?>
 7. _OL_ DISH = OLDISH <only somewhat antique>
 8. <bit of truth> FACE = F_ ACT
15. <reason for war> CASUS BELLI = USB inside C ALLIES*
16. <monarchs> POTENTATES = O TENT inside PATES
18. <beseeches> IMPLORES = IMPS outside LORE
10. <cost> PRICE TAG = RI inside CAPET* _G
22. <plant> ACACIA = CIA after A_ CA
23. SHAM _AN_ = SHAMAN <magician>
25. AH outside RC = ARCH <piece of stonemasonry?>
26. <cardinal> EAST = FEAST - F