Preflop is fine, personally I prefer a flat, but ds your hand is good enough to 3bet. Flop and turn are standar, but river bluff is quite bad in my opinion, you block nothing, the whole board smashes villain's range. You even block K, so there's much less KKxx combos to fold out and QQxx/JJxx could fold naked but are extremely likely to have something in side cards to call. Other than that I dont see him folding pretty much anything in his flop calling range

I think preflop can go either way.  

I would lean towards checking this flop though.  This flop hits flatting range hard, and even if he just flats flop there aren't many turn cards on which we can profitably bet/call; J is our only nut out, and K/Q on turn puts us to an awkward spot, etc.  And obv any cards lower than 8 is bad for us.  If flop was Ts9d4c (two backdoor FD) I'd be much more inclined to c-bet, since you can pick up backdoor FD on turn ~50% of the time.  Also, I think you would have enough rundowns that smack this board in your 3betting range that you don't really need to bet with this specific hand.

I'm not a huge fan of the river bluff, although we have pretty much the bottom of our range.  You can't rep much when taking this line, and it's really hard for him to have naked pairs.. like viktor said QQ/JJ connect with this board very well, and there simply aren't many combos we can fold out.

I think that the PF 3b is fine, flop cbet I can go either way on though.  I would probably cbet this in game with the GS+ BDNFD + overs, but not sure if we have the fold equity on a T9x flop to justify it.

I do not expect the river bluff to work often to make it profitable, it sucks that we have 0 showdown value but sometimes you just gotta give up.

Generally, if you have a close 3B/flat spot HU in BB, think about this:

The fact that you don't have others left to act means there's less to gain by 3-betting. Whereas from the other positions you gain something when the others fold.

You can defend lots of hands HU from the big blind, but it's not necessary to 3-bet a ton, unless you have a clear equity/playability edge or the raiser plays weakly against 3-bets. 

Not really in disagreement preflop, but I would just flat this dangler hand as a default against an early position raiser. Our equities against 15%, 20% and 25% opening ranges are 49%, 51% and 52%, respectively, so we're not pushing significant preflop equity. Against a late position open, I'd 3-bet happily.