The East Bay was still somewhat affordable when I last lived in SV. Walnut Creek is not a bad option, but commute time could very well be suboptimal.
That means leaving at 6:30 to be at the office by 9:00. Yes, it's the Silly Valley, so 9a is early. Counterpoint: it's generally the lower-paid people who need to live further out, because the prices are so ludicrous, that also have more scheduled hours.