It sounds like you are well-qualified and would have no problem qualifying for a Preliminary Designated Subjects Adult Education Teaching Credential. The Commission on Teacher Credentialing is definitely your best resource and will be the way you apply for your credential.

https://www.ctc.ca.gov/credentials/leaflets/designated-subjects-adult-credentials-(cl-697b)

You will work with an approved program sponsor to clear your credential. Each program sponsor has different requirements to clear a credential, so you may want to do some shopping for one that meets your needs. Orange County and San Diego COE used to have strong virtual programs that were fairly affordable.
https://www.ctc.ca.gov/commission/reports/data/approved-institutions-and-programs