That does not mean anything. He could have written the dissent.
I read that Alito was assigned to write the opinions because he had written one less than the others this year, and since this is the closing session, it was simply his turn. Doesn’t mean anything.
Nearly always, when a report says “so and so wrote the opinion,” it means that they wrote the controlling opinion, i.e., the majority opinion.
I DO NOT think Alito WOULD WRITE the dissent!!!!!!