Can you be FIRED for having poor credit in California?

Yes. You can be let go from a job for having bad credit. A lot of employers will hire you on while the credit check is in progress because it takes so long to retrieve. Once that returns, they can let you go. I've had a couple of friends have that happen to them. Usually it's for jobs where you work with money, or have a high amount of responsibility. You are a risk for them to employ.