Hmmm, interesting spot. In my mind I can make a couple of arguments here, flat the raise and see what you can do post-flop, three-bet him or shove over him. The reason I add in the shove is I find large aggro villains (especially ones that will make calls with 86o) will view it as tremendously weak and like to call, with KQo being a pretty strong holding for shoving there. That being said I would really only pull that move if I am in the BB and the last to act and facing the villain heads up. In this situation I think you are right to lean toward playing with him post flop, but how to get there. I think I prefer a 3bet to dissuade either the SB or the BB from coming along. Problem with flatting here as I see it is you are inviting those other two along, and I am not sure I want to see a multi-way pot (something like T9s, JTs I would prefer to invite them, but KQo, I think I want to dissuade them from coming along). So the long answer I come up with is I would 3bet/call all-in with him expecting to be ahead of his range and being in a situation where his aggression may get the best of him.