[betgo]

You may be getting too cleaver raising with Q9o from 4th position. Unless it's the bubble or you have a big stack or something, I don't like it. You are not Amir Vahedi, and I wouldn't try something like that. Q9o is an OK hand in limit or with shallow money, but otherwise it is a terrible trouble hand that just makes 2nd pair or TPNK. If you are going to put in loose raises, it is better to raise with small pairs or suited connectors/gappers. I would rather raise with 74s than Q9o.

Vahedi's could call on the button with a variety of hands. He is probably loose in his requirements since he has position. He may not think much of your play and wants to play a hand with you. It is to his advantage to call, since he is a better player than anyone at the table. He probably has a speculative hand. He could certainly have an ace.

With 2nd pair, I might lead out with a bigger bet or just check. The half pot bet builds the pot out of position without giving you much information or chance to win the pot.

I think you have to call the bet on the river. Since Vahedi could have checked it down, he either has nothing and is making a weak stab at the pot or he has trips or better and figures you won't call a bigger bet. I kind of think he would bet more before this with top pair/trips. Howewver, he might have a weak kicker and be convinced at this point that he is ahead.