Min raise behind, all-in with 99?

[jah0550]

Last night on Party. $30 SNG-7 handed. Blinds t300. Relevant stacks:
MP+2(~2400)
Hero(~2300) on the button
Hero is dealt 9 /images/graemlins/heart.gif9 /images/graemlins/club.gif on the button. It's folded to MP+2. MP+2 min raises(he has been min raising almost every hand since we got to this level of blinds). No one has even called his raise yet, so he keeps taking blinds. MP+2 raises to 600. Hero pushes all-in. Was this the right call? Is it an auto-push with 9s when you have 7-8 times the BB?

[jah0550]

.

[spentrent]

He's been doing all this minraising at this level but he's only up to 2400 chips? This must have been the weakest-tightest table in the universe. Sure, push that 99.