full game, a good tag opens 3-off the BTN, a very loose (the spot in the game) player calls from the CO, an older unknown (possibly on the tight-passive side) calls from the SB and hero calls with A

4

6

9

from the BB.
1) would you call from the BB with pretty much any suited-A hand in this spot?
Flop (4 players, 8 small bets): K

9

3

SB checks, hero bets...
I lead into the pfr, who figures to miss this flop a lot of the time, and put him in a bad relative position. if it comes runner-runner low, I may very well win the low if I can get the pfr to fold.
There aren't whole lot of reasons for players to continue on this flop, being unsuited, mostly disconnected and with only 1 low card.
i'm getting 8:1 on my stab, and I do have a bunch of good turn cards to catch (either for my actual hand or for hands I might be able to represent), allowing me to fire a likely profitable second barrel.
I'd probably also take a stab if the pot weren't raised before the flop, because even though I get worse price on my steal attempt, I stand a better chance to win, expecting no resistance in a small pot unless my opponents have K+straight draw, kings up or better, or QJT*...
I wouldn't tag my bet as a "complete steal", probably more of a "thin semi-bluff". I wouldn't like to stab too often, otherwise opponents may catch up.
my alternative is check/folding. the added value of getting hands to fold might make a bet slightly profitable, while check/calling clearly isn't.
2) Do you think I have enough to make a thin semi-bluff in this spot?
3) What otherwise marginal hands would you consider leading with in this spot?