When Ben destroyed his mask, that was a symbolism of him ditching his ways as being a Darth Vader impersonator. He was berated by Snoke, and while I still believe he looks up to Anakin as Vader, he isn’t going to go around wearing a mask anymore, as he has become his own self, yet still conflicted inside. I really hope Ben doesn’t start wearing the Kylo Ren mask in Episode IX, as its backtracking on himself as a character, like nothing has happened to make him decide to stop acting like Vader.
Or, Ben has regressed to needing to hide behind a mask after Rey’s rejection. I don’t think Kylo will be in a good place emotionally when we see him in IX, so he could be using the mask as a reforged identity.