NL50SH A9o Top Two - Turnplay?

NL Holdem $0.50(BB) Replayer
SB ($53.55)
BB ($35.45)
UTG ($18.25)
Hero ($50)
BTN ($49)

Dealt to Hero 9 :spade: A :heart:

fold, Hero raises to $1.75, BTN calls $1.75, SB calls $1.50, fold

FLOP ($5.75) A :spade: 4 :heart: 9 :diamond:

SB checks, Hero bets $4.50, BTN folds, SB raises to $11, Hero calls $6.50

TURN ($27.75) A :spade: 4 :heart: 9 :diamond: 6 :club:

SB checks, Hero bets $12, SB raises to $40.80 (AI), Hero?