Seriously?
Why do we want to just flat here with a hand that beats large proportion of his range? Surely were just burning $$$ flatting here letting him get ahead?
If we 3-bet, where's our profit coming from? We stand to win his 4BB, but we put ourselves in a big pot with reverse implied
odds when we see the flop; where our opponent has a much better chance of playing perfectly than we do.
I don't think this is a big leak either way, but the
hands that call us will probably play correctly against us a very large portion of the time after the flop comes. What's almost certainly going to happen is that we're going to bet the flop when it's checked to us. Or?
And if we c-bet, we're in a situation where any overcard hands to ours that called the 3-bet will be able to continue when we're beat and fold when they're beat, which is a terrible situation for us. Some of the time, we'll get calls from worse hands (lower pocket pairs) on a flop that doesn't look scary to him, but lower PPs are a fairly small part of his range, and I think we can squeeze more value out of them by letting villain keep the initiative.
There's some fold equity involved in 3-betting 99, because we get to fold hands like QJo and KT and whatnot (that are mostly a coinflip versus us) but the fold equity for that is only a percentage of $4.
I'm by no means certain about these plays and I haven't filtered any results in HEM (which I probably should), but generally speaking, I think he has us caught in a spot where we probably have the best hand but we won't make a lot when we do, and we'll lose a lot more when we don't.