There’s a ten day stay in effect, for a CA resident they must wait until 10 days after the ruling to purchase a magazine.

But in any time between then and any potential stay issued by the 9th Circuit Court, if the AG pursues the case further and is granted one, they could purchase one and maintain possession even if the law is later upheld. To the best of my knowledge that’s how CA handled the prior two ‘Freedom Weeks’ (When lower court rulings had been overturned upholding the law).