It is 9.3% on income after $58k until $300k (single filing), but the first $58k is taxed at a lower rate, so you never get anywhere near an effective 9% rate. That’s just the way marginal rates work, Republicans throw out the top tax rate to argue that California is high taxed, but it turns out the taxes are very progressive (the first $100k is taxed very lightly).
He should have tenure. The UC system doesn’t pay that great, and there is also a lot of competition for faculty positions. Your best bet is to make some money on the side , legally of course, advising some company, but even that has a lot of restrictions.
They're not low, certainly, but they aren't extravagant, and they are offset by low property taxes (California 1%, Texas 1.80%, New Hampshire 2.18%), even more so once you've been in a place some years, and are benefiting from Prop 13.
Sure, if housing prices increase at the same rate as the last 30 years there is a huge benefit, but regardless if you buy today you’ll have a massive property tax bill.