PLO8 $25 Calling a big bet on the river with 2nd nut straight

[Turlock]

PokerStars Pot-Limit Omaha/8, $0.25 BB (9 handed)
SB ($12.40)
BB ($26.60)
UTG ($15)
UTG+1 ($14.75)
MP1 ($23.50)
MP2 ($27.70)
Hero ($22.90)
CO ($8.55)
Button ($23.50)

Preflop: Hero is MP3 with A[img]/images/graemlins/diamond.gif[/img], 2[img]/images/graemlins/spade.gif[/img], T[img]/images/graemlins/club.gif[/img], J[img]/images/graemlins/heart.gif[/img].
UTG calls $0.25, UTG+1 calls $0.25, <font color="#666666">2 folds</font>, Hero calls $0.25, <font color="#666666">2 folds</font>, SB completes, BB checks.

Flop: ($1.25) 9[img]/images/graemlins/club.gif[/img], K[img]/images/graemlins/spade.gif[/img], 8[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(5 players)</font>
<font color="#CC3333">SB bets $0.75</font>, BB folds, UTG calls $0.75, UTG+1 calls $0.75, Hero calls $0.75.

Turn: ($4.25) 7[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(4 players)</font>
SB checks, UTG checks, UTG+1 checks, <font color="#CC3333">Hero bets $4.05</font>, SB calls $4.05, UTG calls $4.05, UTG+1 folds.

River: ($16.40) T[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(3 players)</font>
SB checks, <font color="#CC3333">UTG bets $9.95 (All-In)</font>, Hero ????

Final Pot: $36.30

Can I call this bet? I'm new to the game,coming from Hold Em,and am slowly coming to terms with how important it is to have the nuts.
My thoughts at the time of this hand were that I was telling myself that as it was only a $25 game I have a reason to believe he doesn't have to have the nuts.