No they would not bench him unless he keeps attacking his own people in public and denies to work hard in the training sessions. Otherwise the authority of Enrique would severely be undermined if Mbappe can do whatever he wants, perhaps even comes home late from short trips and stuff, and he still plays the games.
But never forget that Mbappe sometimes has this losing body language on the field when the game doesn't go well. He tends to complain about others as well and if he realizes that there is nothing to be won for that PSG team in the Champions League, the whole PSG - Mbappe connection could end with an even bigger bang than it is already.
I am sure that they can bench him if they want to but they need the go ahead from the management as well. I mean it's all about how you could end up with getting rid of a player, if you do not play him and make it very clear to him that you are not going to play him, then he will leave himself. This requires the team to realize that they want to get rid of him no matter what.
But since PSG is a French team and Mbappe is France superstar, I feel like they will get a lot of heat if they do not play him and that's why I am expecting him to play in every game he can. The way to get rid of him is to just make sure you talk to the agent and make it known that you do not want him on the team, if you can do that then it should be fine.