25 PLO middle set on drawy board

[devilbiss]

No reads on CO only played a few hands with him so far. Have a pretty good history with button and he is very laggy and is definitely drawing here with his smooth call.
So do we call here or shove and why?

PokerStars Pot-Limit Omaha High, $0.25 BB (6 handed) pokerhand.org hand converter

Button ($21.95)
Hero ($36.40)
BB ($22.10)
UTG ($34.40)
MP ($48.30)
CO ($15)

Preflop: Hero is SB with A[img]/images/graemlins/heart.gif[/img], 6[img]/images/graemlins/spade.gif[/img], 6[img]/images/graemlins/heart.gif[/img], 9[img]/images/graemlins/spade.gif[/img]. CO posts a blind of $0.25.
<font color="#CC3333">UTG raises to $0.75</font>, MP calls $0.75, CO (poster) calls $0.50, Button calls $0.75, Hero calls $0.65, BB calls $0.50.

Flop: ($4.50) 2[img]/images/graemlins/club.gif[/img], 9[img]/images/graemlins/diamond.gif[/img], 6[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(6 players)</font>
Hero checks, BB checks, <font color="#CC3333">UTG bets $0.5</font>, MP calls $0.50, <font color="#CC3333">CO raises to $6.3</font>, Button calls $6.30, <font color="#CC3333">Hero ?