100NL ....why would he check the turn?

[Belok]

PokerStars Pot-Limit Hold'em, $1.00 BB (8 handed) pokerhand.org hand converter

MP2 ($186.35)
CO ($18.55)
Button ($98.50)
SB ($100.50)
BB ($54.55)
Hero ($97)
UTG+1 ($97)
MP1 ($248)

Preflop: Hero is UTG with K[img]/images/graemlins/spade.gif[/img], K[img]/images/graemlins/heart.gif[/img].
<font color="#CC3333">Hero raises to $3.5</font>, UTG+1 calls $3.50, <font color="#666666">6 folds</font>.

Flop: ($8.50) Q[img]/images/graemlins/club.gif[/img], 9[img]/images/graemlins/heart.gif[/img], 2[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $6</font>, <font color="#CC3333">UTG+1 raises to $15</font>, Hero calls $9.

Turn: ($38.50) J[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, UTG+1 checks.

River: ($38.50) 9[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $19</font>, <font color="#CC3333">UTG+1 raises to $78.5</font>, Hero calls $59.50 (All-In).

Final Pot: $195.50


Villain is 13/3/3, which leads me to think he'd be aggressive enough with his made hands. The turn check really threw me off, considering how incredibly drawy the board is.

His flop raise made me think 99/22, but I obv couldnt just fold there.

The turn was SOOOO drawy, that i couldnt see any made hand checking behind. At this point I'm thinking AKhh or maybe AQ is his hand.

So i make my medium value-bet on the river and he pushes. WTF? 99 is pretty much out of the question now. I cant see him checking a vulnerable hand like 22 behind. So I did what I always do in situations that dont make sense - I called.

Thoughts?