I don't use credit cards. Can I use a debit card at SFO?

Yes, if you have proof that you have a departure flight out of SFO also.

I use Enterprise often. They put a$50 hold on my debit card.

Can I rent a car with debit card if I live San Francisco??

Try considering a credit card OR load as you go card. Yes, you can still use it, but like it is the main payment method

Debit cards are terrible. There's no cash back points on them.