Bad all in?

Charity Tournament play.
On table with 4 of the 6 opponents for last 31/2 hours. Opponents play regular house games and casino cash games. Players play loose preflop but afterward play pretty solid.
Hero has played in 2 previous hands all night.
1st one a limp from the BB, hero called a bet on the turn and checked through through the river.
Second hand called a raise from the biind and folded on the flop.
The hand in question
6 handed 200/400
Hero is in the small blind with A9o with approximately $4500 in stack. Hero has one of the shorter stacks at the table. (a couple people have been cycled onto table this has been most conserative table in tournament)

4 limpers, Hero completes, BB checks
Flop
A 3 4 rainbow
Hero goes all in......
Is this a bad call?
I am a newbie. Normally play limit holdem 50000+ hands on Party 2/4.positve 1 bb/100.

What kind of A hands greater than A9 would you expect to call me on this bet? Assume you have the same stack size or higher than me.

Been playing 2 hands only in 3 1/2 hour? You must have a REALLY tight image by now.

Why I would push:

1) If it all get folded down, you will still win 2400 and make a profit of more than 50% of what your stack was when the hand started.

2) This being sixhanded and you would be left with 4100 and blinds at 200/400 if you check/folded the hand now. I would act now when I still can do some serious damage.

I am only worried about the 9 as the kicker here since if you do get called, you are likely to be behind but it's hard putting someone on AJ+ without any preflop action and you can probably make someone fold A10 here with your push.