5/10 NL hand (#1)

[ArtVandelay]

playing in a fairly soft 5/10 NL home game, although a few players know what they're doing... villian in this hand is new to me and has been playing loose-aggressive, but I haven't seen any of his hands so I don't really know if he's any good or not... I have 1.2k and he has me covered

4 limpers, SB completes, and I check in the BB with J9s

flop comes KdJx9d; SB leads 50 and I raise it to 200... folded to villian in middle position who makes it 500 and it's folded back to me; what's my play?

suppose I decide to call and the turn is an offsuit 8; what do I do then?