I don't think TyTy will start initially. I feel a lot of people here are underestimating the adjustment he'll have to make to play at this level. He may start after he's proven himself with quality minutes - I just don't think he starts right off the bat. Of course a lot will argue that Cal will start him just because he's a 5-star.
I also think that people here see his highlight videos and assume he's this amazing 3-pt threat. I found some game stats, and against tougher competition he didn't shoot so great - went 1/8 and 1/6 from 3 in losses to Monteverde Academy, and 2/7 in a win over Wasatch (with Nolan Hickman). He had some good 3-pt shooting games too, but probably not against the greatest defenses. I wish stats were kept as diligently at the HS level as they are in college, but unfortunately we have no idea of his season stats for FG%, 3FG%, RPG, APG, etc., at least not that I can find online.
Of course I might be wrong. And I'm not saying he won't be a great player, I just think some people's expectations might be a little unrealistic.