Need some advice on playing QQ on A-high flop

[maddo]

$10 NL Online MTT

75/150

LP ~3000
Hero ~4500

LP limps
Hero on button raises to 500 with QQ
SB+BB fold
LP calls

Pot=1025

Flop: A99 (2 Hearts)

LP bets 150

What is the most likely reason for players doing this? Holding a weak ace? Flush draw? Underpair?

Pot=1175

Hero raises to 600

Is this a fair raise to try and find out if Queens are good? It felt like a waste of chips because LP did this:

LP reraises (minimum) to 1050

Pot=2675

Here I thought about calling the 450 just to see if I could get lucky and hit a Q, but decided to get out and save as many chips as I could for later. Should I always call here?

Can anyone offer some analysis?

Cheers.