Safari kept crashing for me (and occasionally other apps, but don't know if related, just thought they were buggy apps) on my iPhone 5. I originally thought it was a problem with some sites being horribly broken, but it was also happening on mainstream sites such as wsj.com.

After I installed the 9.3 update, the crashes stopped. Maybe the firmware update and device reset clears that database.

Or it could be completely unrelated. Whichever, that's my anecdote.