First thing I want to say is I wouldn't even be in this hand because I don't think there is any point in playing during the rebuy period on Bovada.  The way it works is you get X amount of chips for Y dollars, then during the first break you can add on 5X chips for Y dollars.  I think its way better just to wait for the first break and pay 2Y dollars for 6X chips.

As far as the hand goes I don't like the 3b with 99.  During the rebuy period you're not going to get very many folds, and (I think)most flops have an A, K, or Q, and with 3+ other people in the pot one of them most likely has top pair or better.  99 plays better as a call, especially if you don't have to worry about a 3b happy table.

The cbet could be smaller I think, 500 accomplishes the same as 725.  Turn check is good.  I don't think he's folding anything he called the flop with.  River I would fold.  It's possible he's bluffing, but not enough to justify a call.  The strategy most people take is to call a lot of hands hoping to hit big, then bet big when they do hit.  They typically don't try to bluff big in the rebuy period.