This is useless to me, since Lacerte has indicated they have no intention of accommodating Tax Preparers by allowing the program to take advantage of these extended deadlines.  I now have clients who are upset with me that I'm unable to have their payments processed in October.

Hard to believe Lacerte isn't planning on fixing this. Where did you get your information?

Directly from Lacerte.  See this other thread where others have been told the same, as recently as today:

https://proconnect.intuit.com/community/lacerte-tax-idea-exchange/may-15-due-date-change-for-storm-d...

But has California conformed to this new ruling ?  

Yes - per a flash alert just sent out by Spidell

https://www.gov.ca.gov/2023/03/02/more-time-to-file-state-taxes-for-californians-impacted-by-decembe...