Both villains are somewhat loose players

PokerStars No-Limit Hold'em, $0.05 BB (6 handed) Poker-Stars Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

Button ($14.13)
SB ($10.28)
BB ($1.69)
Hero ($3.60)
MP ($10.18)
CO ($11.84)

Preflop: Hero is UTG with 9, 9.
Hero raises to $0.2, MP calls $0.20, 3 folds, BB calls $0.15.

Flop: ($0.62) 8, 4, 7 (3 players)
BB bets $1.49 (All-In), Hero calls $1.49, MP calls $1.49.

Turn: ($5.09) Q (3 players, 1 all-in)
Hero checks, MP bets $8.49 (All-In), Hero ???

You can't flat 1/2 your stack on the flop

Push or fold, most likely pushing because his line doesn't make a ton of sense for any hands that beat you..This is taking into account the level you are playing, I'm assuming its awful

easy push on the flop

Fold and wait for him to do it again when you have a real hand.

If you are going to go on the flop, go all in. What are you going to do with the other half?

Shove flop, but as played, fold turn.

Actually, thats probably a call.
Thing is you cant call the flop and fold the turn. The money is too good, and hands like A8, or even 8x is all over his range here if he is loose.
If he thinks he has you beat on the flop, he is not going to slow down on the overcard when you check.