There is no provision for a waiver from the rabies vaccine in California law:
http://www.theanimalcouncil.com/file...ION_121575.pdf
With that said, if your dog is not current on her vaccine, they don't throw you in jail.
The risk is that if she were to bite someone or be exposed to rabies, she would have to be quarantined and/or could get the disease. That is the same scenario as states who do allow a veterinarian's waiver.
I am in the same situation with Lady. At thirteen with both diabetes and liver damage from years of anti-seizure medications, she can't have a rabies vaccine. The one four years ago nearly killed her. I have minimized her risk by only letting her out on my deck now and walking her in her stroller. At her age, that's fine with her. In fact, she loves her stroller rides!