$25NL Two Pair Facing River Push

[Grindaments]

Full Tilt Poker - No Limit Hold'em Cash Game - $0.10/$0.25 Blinds - 4 Players - (LegoPoker HH Converter (http://www.legopoker.com/hh))

SB: $28.55
BB: $46.30
UTG: $55.50
<font color="black">Hero (BTN): $29.55</font>

<font color="black">Preflop:</font> Hero is dealt J/images/graemlins/heart.gif 9/images/graemlins/heart.gif (4 Players)
UTG calls $0.25, <font color="red">Hero raises to $1.00</font>, 2 folds, UTG calls $0.75

<font color="black">Flop:</font> ($2.35) 5/images/graemlins/spade.gif 6/images/graemlins/diamond.gif 9/images/graemlins/club.gif (2 Players)
UTG checks, <font color="red">Hero bets $2.00</font>, UTG calls $2.00

<font color="black">Turn:</font> ($6.35) 2/images/graemlins/diamond.gif (2 Players)
UTG checks, <font color="red">Hero bets $5.00</font>, UTG calls $5.00

<font color="black">River:</font> ($16.35) J/images/graemlins/diamond.gif (2 Players)
<font color="red">UTG bets $24.25</font>, Hero ?

Had been playing quite aggresive raising the last 4 pots here and thought maybe villian is letting me generate action for his big pair. The small pair limp hitting a set is of course the other possibility