If you are asking if you can still e-file your State and Federal return without filing a CA extension, the answer is Yes. If you filed a Federal Extension back in April, it is automatically extended. The only time a separate CA extension is filed is if you anticipate you owe money and you are sending in a payment with it.
If you did not file a Federal extension, you will still be able to efile. Your return, however, will be late. Federal penalties are based on the tax due upon filing.
If you are getting a refund there are no late fees. If you have a tax due and you're in a california disaster area both the returns and payments are extended to Oct 16.
IRS statement on California tax returns and payments extended to October 16, 2023