At 150/300 you do not have a lot of room to play. Any hand you'd raise with 9 BBs there, you should be shoving. Say you raise to 800 and BB shoves. You'd have about 1900 left in your stack, and the pot size would be about 4100. You're getting better than 2:1 and have invested nearly 30% of your stack on this hand already. Or if you raise to 800 and BB calls. You're down to 1900 chips, the flop comes
[7s][5s], and the pot is about 1800. What else can you do but shove on that flop? This is why you just shove pre-flop if you have a good enough hand with 9 BBs.
At 100/200, that changes things a lot. This is a tough situation because of your medium stack. If you raise 2.5 or 3x bb, get called, and he checks to you on the flop, you're going to toss out another 3 or 4x bb on a continuation bet. So you'll be risking somewhere around 1200 chips, which is nearly half your stack!
There's nothing wrong with folding here.
With passive pre-flop players in the blinds, you can also open-limp on the button with the intention of betting whenever they check. The pot will be smaller so you won't need to risk as much. A good post on it in 2p2 by Raptor
http://forumserver.twoplustwo.com/showf ... art=1&vc=1
With tight players in the blinds, a raise to 550 is good simply because they will fold so much pre-flop. It's going to suck having to make a continuation bet against them because of how much you need to risk, but like I said, they will fold pre-flop enough to make this raise worthwhile.