He used to speak in quite certain terms about turning pro after Pyeongchang, no? And then at some point it became "half, half" during an interview. At another one, it was "not going to think about it, want to focus on Pyeongchang for now".... I agree with this recent talk about quads, etc, that it sounds like there are things he want to try and complete post-Olympics. So what with Saitama being the location for Worlds 2019, he might want to compete there as well.
Several people here have made convincing points about the potential of 4Lz being swapped in, perhaps as early as next season? Probably it depends on Yuzu's progress, but Brian (ice network podcast in December?), who's more conservative about these things, mentioned 4Lz in the horizon, which lends weight...