10-20 live, do i bet the low end straight for value?

[ANY2CARDZ]

Im in middle postion, first in with 99, i raise pre-flop to mix up my play, as i have been pretty tight and players usually show respect to my raises. Lp calls button calls, and bb calls, who is a loose-passive type.
Flop:
8s,10h,Qd, it gets checked around,
Turn:
Jh , BB bets, i raise, LP and button fold. BB calls, and then checks blind.
River: Ks, i check.

I thought this was a pretty standard check as bb may have been on a-j, or a-10, and maybe a-q, but an friend of mine made a comment that if he checks blind, then you have to know he is not on a draw, and therfor can bet for value. What would you do in this situation, and please feel free to give any input on checking blind in general and what it usually means or can mean, I can never seem to make too much sense of it. Thanks

[Moneyline]

Preflop: I don't think you should open raise 99 from MP to mix up your play. I think you should open raise it because you likely have the best hand and want to get all the value you can out of it before the flop.

Flop: I'd bet to increase my chances of winning a pretty decent sized pot, but I admit checking is also at least a viable option on a coordinated flop with 2 overcards to your pair. I'm interested to hear what others have to say about this.

Turn: I like your raise because it puts pressure on flush draws or anyone holding an A or K.

River: IMO, people check blind for all sorts of reasons; some of the reasons are logical, but most are not. It's very difficult to interpret irrational moves using logic, so I'd just play the percentages here and value bet if this is the sort of opponent who will pay you off with less than a straight (and I get the impression he is).

[ANY2CARDZ]

He ended up having q-10. If he didnt check blind, i would have bet the river thinking that if he hit his straight he would bet out. But im still not sure about checking, i mean if raises i loose two bb extra, and he might only call my river bet 30% of the time wiht that board. thanks for the input!