Attacking the school is a bad plan, too many powerful people, and Iruma is basically invincible being able to avoid danger like that, and he can summon Kaleigo, and he has the Ring, and he has his bow. No, I think the plan was just to get in contact with that woman. if Kiriyo gets near Iruma, Iruma will know something is really wrong, and even if he doesn't attack him, he will call the teachers, beginning with Kaleigo, who even in his fluffy form can still pack a good punch. But, he can review that Iruma is a human, but I don't think he would do that, it's too risk someone else would eat Iruma, and he wants him to himself.