NL25, flopped set called my ch/raise turn play?

[pacman2k7]

Villain is a nit 9/7/2 ..

After his call on flop, and turn brings an Ace, may I think I should fold my sets? AK is the only hand I can beat here..

Poker Stars - No Limit Hold'em Cash Game - $0.10/$0.25 Blinds - 5 Players - (LegoPoker Hand History Converter)

SB: $24.00
Hero (BB): $24.55
UTG: $52.20
CO: $60.85
BTN: $31.25

Preflop: Hero is dealt T[img]/images/graemlins/heart.gif[/img] T[img]/images/graemlins/club.gif[/img] (5 Players)
UTG calls $0.25, CO folds, <font color="red">BTN raises to $1.25</font>, SB calls $1.15, Hero calls $1.00, UTG folds

Flop: ($4) 9[img]/images/graemlins/spade.gif[/img] K[img]/images/graemlins/club.gif[/img] T[img]/images/graemlins/diamond.gif[/img] (3 Players)
SB checks, Hero checks, <font color="red">BTN bets $3.50</font>, SB calls $3.50, <font color="red">Hero raises to $12.50</font>, BTN calls $9.00, SB folds

Turn: ($32.50) A[img]/images/graemlins/diamond.gif[/img] (2 Players)
<font color="red">Hero ??