The best way to judge a neighborhood is to spend time in it. Go to parks, coffee shops, neighborhood markets, and talk to people. Most areas in Silicon Valley are "safe" enough that other factors are going to decide how much you like it.
You've already been provided with the crime reporting web sites. You also need to keep in mind that a "safe" neighborhood may show up poorly in recent reports because an out of area crime group has found that everyone leaves their doors unlocked...
Top 2 agent nationwide at Keller Williams Realty
Over 30 years experience
Over 1,000 homes sold in Santa Clara and San Mateo Counties