I have seen it take a year or more.
My standard disclaimer: I am not offering legal advice, assume I do not know the law in your state and that I am just making suggestions for starting points for when you do speak with an attorney. Do NOT rely on anything I write and contact a lawyer in your area immediately after reading my posting.
While California appellate court try to get cases out within 6-9 months, I agree that it often takes more than a year. At a certain point, the Court of Appeal will advise the parties whether it believes oral argument is necessary and inquire whether either side seeks oral argument. Generally, that notice is not sent until the appellate court has completed its analysis of the briefs and is ready to rule.