200PLO turned nut flush on paired board

[Vinetou]

PokerStars Pot-Limit Omaha High, $2 BB (6 handed) Poker Stars Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

BB ($64.25)
UTG ($44.40)
MP ($204.05)
Hero ($228.40)
Button ($231.65)
SB ($201)

Preflop: Hero is CO with A[img]/images/graemlins/club.gif[/img], 6[img]/images/graemlins/heart.gif[/img], Q[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/diamond.gif[/img].
<font color="#666666">1 fold</font>, MP calls $2, <font color="#CC3333">Hero raises to $9</font>, <font color="#666666">3 folds</font>, MP calls $7.

Flop: ($21) 8[img]/images/graemlins/diamond.gif[/img], K[img]/images/graemlins/diamond.gif[/img], 5[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
MP checks, <font color="#CC3333">Hero bets $19.95</font>, MP calls $19.95.

Turn: ($60.90) 5[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
MP checks, Hero checks.

River: ($60.90) 9[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">MP bets $26</font>, Hero calls $26.

Final Pot: $112.90

I am a noob in omaha so bare with me, please.

Last few hands I have been running over villain a little bit so he is probably a little frustrated. My image is probably aggressive.

Generally, how do you deal with those situations? Ciaffone suggests making a probe bet, a little less than a pot, but I chose to check here and call his river bet (I would probably call even a potsized bet, is that correct?) because I didn't want to get raised out of my hand (he might do it with weaker flush because of my aggressive image, I guess).