First, there is no "kernel exploits from vulnerable games" as games are applications that run in the OS (FreeBSD based). What happened with the PSP is that game

First, there is no "kernel exploits from vulnerable games" as games are applications that run in the OS (FreeBSD based). What happened with the PSP is that game exploits can be used to run code that trigger kernel exploits (which have to be found separately and are a lot harder to find). In terms of game exploits on the PS4; there is no doubt that such vulnerabilities exist, but you're limited to ROP (no JIT in games) in userland.