AK TPTK reraised with no scare on board ?

[cbloom]

Villain is a bit on the loose side, but not a nut/donkey. I've been betting continuation on almost every pot I raise preflop, and he's been (correctly) calling my continuation bets with a lot of hands.

Party Poker Pot-Limit Hold'em, $ BB (10 handed)

saw flop|<font color="#C00000">saw showdown</font>

UTG+1 ($99.58)
UTG+2 ($197.20)
MP1 ($29.95)
MP2 ($110.55)
MP3 ($50.80)
CO :#A500AF(Villain)/ ($100.15)
Button ($94.95)
Hero ($108.95)
BB ($113.15)
UTG ($55.80)

Preflop: Hero is SB with K[img]/images/graemlins/spade.gif[/img], A[img]/images/graemlins/diamond.gif[/img]. UTG+1 posts a blind of $1. Hero posts a blind of $0.50.
<font color="#666666">1 fold</font>, UTG+1 (poster) checks, <font color="#666666">3 folds</font>, MP3 calls $1, CO :#A500AF(Villain)/ calls $1, <font color="#666666">1 fold</font>, <font color="#CC3333">Hero (poster) raises to $4.5</font>, <font color="#666666">1 fold</font>, UTG+1 folds, MP3 folds, CO :#A500AF(Villain)/ calls $4.

Flop: ($13) J[img]/images/graemlins/heart.gif[/img], 9[img]/images/graemlins/club.gif[/img], 7[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $9</font>, Villain calls $9.

Turn: ($31) A[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $20</font>, Villain raises all in [$86.15] Hero ???.

What do you put him on ?