Against opponents who will always bet this texture when checked to, we need a x/r small range so we can do it as a bluff. On this board I think the hands that the villain is bet-calling against our small x/r with good equity are rare and we don't need to worry about it that much. I guess there are some pair + gut shots or pair + open enders but I feel like most of these marginal hands are going to check back the flop anyways. 

I think this board is different in that it will hit more of your 3-betting range whether it's an over pair with fd or any rundown really with or without fd. So I don't mind c-betting especially if the villain is prone to check back his weaker draws and air on this spot. X/r is fine too as you can get in very good against weaker wraps (which might just call a c-bet). You can also get an extra bet out of stab happy opponents you otherwise wouldn't. On this texture I don't think you need a x/r small range so you can just jam over any bet. 

I would like to add that with your pair of 9's you actually have decent showdown value and you're crushing most wraps with no pair or a lower pair. But I don't think that's really significant in terms of what line you should choose. You're probably still not getting any two pair or over pair with a fd to fold with a x/r. Dry over pairs aren't likely to bet anyways. So I would choose between betting and x/r'ing based on villains tendencies. If he's on the aggro side and gets it in light on these boards I like x/r. If he's more passive I would just c-bet away. 

For some reason I forgot I had top pair as well... So in this case it looks like a clear bet-get it in or check-raise for value (or anyway, value-ish...very strong hand that is best suited to playing aggressively).

I think check-jamming is really a valid option here. I just think that most opponents will bet a polarized range here of nuts and air and check back with the sort of hands we have poor visibility like pair + over cards or pair + a gut shot. I'm also worried that if we don't have a strong enough check calling range on a board like this, we end up folding too much either on the flop  or on the turn. We definitely can't have just a x/r range and a x/f range. With that said hero's particular hand could fall in either x/r or x/c range depending on opponent's betting range. 

If you cbet this texture as a default, opponents can exploit you easily by raising with a decent frequency. You're just not going to make enough hands to bet-jam. If you only cbet with strong hands that's exploitable too. So I like checking as a default against good opponents. 

sry for the confusion. I mean i always cbet with overs+fd at this board. If he is attacking this board a lot. c/r is also an option.

In a vacuum that might be fine, but it's not a very good way to play your range.

I think one of the best benefits of creating a balanced x/c range on a board like 234 is that we can include some of our dry over pairs in it, especially aces which is going to have good equity against opponent's range but sucks to bet-fold. We just have to make sure our x/c range includes strong made hands so that we won't allow our opponent to relentlessly barrel us of from our hand every time.