It’s an EO, so California doesn’t have to follow it. However, they would quite wise to do so as I doubt that much of their (legal) immigrant culture wants to see their daughters getting smacked around and having to shower with guys.
They can show their independence, their sports programs don't need any federal funding. California is rich and can stand alone and refuse all those federal dollars.
I like the way they are willing to stand alone, to stand for the universal principal that trans men can really become the sports queens they were born to be.