AQ hand on a river scare card

[|~|ypermegachi]

i'm watching a training video for a 1000NL shorthanded game...the play seems not right to me, and the guy doesn't go into too much detail.

anyways, Hero is AQo in the BB. UTG limps $10, SB completes, Hero raises $40. UTG calls $30, SB folds.

flop, $90 pot. QJT no flush draw.
Hero bets $90, UTG calls.

turn, $270, blank.
Hero bets $150, UTG thinks and calls

river, $570, 8 falls.
Hero checks, UTG bets $250, and Hero calls.

he checked because he feared his opponent might have a 9, but called because he thinks it was a bluff and that he has top pair. this was the 1st hand of the session with no real reads. what should be going through my head if i check it to villain? this hand looks more of a induced bluff, but where do you draw the line of how much to call?

[gabe]

i would rather lead river and fold to a raise. i dont think someone calls down with a 9 here very much, but you see stuff like KQ KJ AJ KT instead.

the bet is small enough that maybe its just KQ thinking its good.