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.
If PSG has made a bad decision against Mbappe, I don't think PSG's decision will be well received by the French fans. The ferocious attitude of the French fans towards Messi and Neymar has already been revealed, so if the club makes a bad decision against Mbappe, the French fans will not leave the club. PSG have confirmed that Mbappe's verbal agreement with Real Madrid has been completed just one year before Mbappe's move to Real Madrid. Before Mbappe left for Real Madrid, he had a big offer from the Saudi League but I don't know exactly what Mbappe will do about that offer. But if there was any other player in place of the kind of big offer that was made to him, he would have accepted this Saudi offer without thinking. Now it remains to be seen what decision Mbappe ultimately takes