Theme: Face the music - The word on the RIGHT side of a theme entry can precede FACE. The music was my idea.
17A. What buck passers "play" : BLAME GAME. Game Face. Psyched up for the big game?
21A. Holiday song first popularized by Eartha Kitt : SANTA BABY. Baby Face
38AS. You might stand pat in it : DRAW POKER. Poker Face
58A. Navy stunt pilot : BLUE ANGEL. Angel Face
64A . Drill sergeant's directive ... and, literally, what the ends of 17-, 21-, 38- and 58-Across can each have : RIGHT FACE
Argyle here. I tried ABOUT FACE first; BZZT, wrong. Everything else was C.C. smooth.
1. Zen garden growth : MOSS
5. Arthur of tennis : ASHE and 68A. Masterful tennis server : ACER and 69A. Monica of tennis : SELES
9. Toss back and forth, as words : BANDY
14. __ and for all : ONCE
15. Fishing line holder : REEL
16. Be wild about : ADORE
19. JCPenney competitor : MACY'S
20. Former baseball commissioner Bud : SELIG
23. Hits gently : TAPS ON
25. Arrest : NAB
26. Maiden name intro : NÉE
27. Holiday threshold : EVE
28. Weeping, perhaps : SAD
30. In disagreement : AT ODDS
33. __ meat : RED
34. "A bit of talcum / Is always walcum" poet : NASH. (Ogden Nash)
37. God of love : EROS
41. Auth. unknown : ANON.
43. Back of the neck : NAPE
44. Navig. tool : GPS. (Global Positioning System)
47. Some stoves : AMANAs
49. Tailor : SEW
51. Insistent knock : RAP
52. Drill insert : BIT
53. "Mazel __!" : TOV
56. Italian deli sandwich : PANINI
62. One with wanderlust : NOMAD
63. Countesses' spouses : EARLS
66. Rhubarb unit : STALK
67. Island near Corsica : ELBA
70. Ultra-fast jets : SSTs.
71. Brewed beverages : TEAs
1. Many a character in "The Godfather" : MOBSTER and main character - 38D. Crime family leader : DON
2. Temporarily not working : ON LEAVE
3. Sold for a quick profit, as tickets : SCALPED
4. Loading dock trucks : SEMIs
5. Chile neighbor: Abbr. : ARGentina
6. Salty waters : SEAS
7. Muscle beach dude : HEMAN
8. Court colleague of Ruth and Sonia : ELENA. Ginsburg, Sotomayor, and Kagan.
9. The Crimson Tide : 'BAMA. Alabama Crimson Tide, national college football champions.
10. Very little : A DAB
11. "Impossible" : "NO CAN DO"
12. Signs of prolonged drought : DRY BEDS. (river beds)
13. "I completely agree!" : "YES, YES!"
18. Showbiz clashers : EGOs
22. "Check back later," in a sked : TBA. (To be announced)
24. Grandma : NANA
29. Light before sunup : DAWN
31. Concert shirt : TEE
32. Bobby of hockey : ORR
35. Mother's Day indulgence : SPA
36. Short plane trips : HOPS
39. Genetic letters : RNA
40. "__ your chin up!" : KEEP
41. "Have we started yet?" : "AM I LATE?"
42. Without additives : NATURAL
44. Pained expression : GRIMACE
45. It'll cure all ills : PANACEA
46. Little web masters : SPIDERS. Cute.
47. Convent overseer : ABBESS
48. LIRR stop : STN. (station)
50. Desire : WANT
54. Fairy tale baddies : OGREs
55. Bridal shop buys : VEILS
57. Jack Sprat's restriction : NO FAT
59. InStyle competitor : ELLE
60. Poses a question : ASKS
61. Pride parade letters : LGBT. (lesbian, gay, bisexual, and transgender)
65. Owns : HAS