Oh, I thought it was just based on being top 9% in a CA high school. So I guess OP needs to apply to Merced if that’s desired as a safety. But the need to apply also means OOS status vis-a-vis tuition, so a more affordable backup plan would probably be needed.
The other unfortunate thing about UC’s is that they don’t routinely grant deferred admission. So OP can’t nail down admission and then take a gap year if the residency ducks aren’t in a row yet; they’d have to reapply if a delay is needed.