How do you understand Ananda Sutta?
Like the sutta explains, if the Buddha said there is a self it would be wrong since it comes under eternalism. If the Buddha said there is no self, Vacchagotta would have taken it as Annihilationism. Vacchagotta's mind was probably capable of grasping only one extreme or the other instead of viewing things as mere experiences rising and falling. That's probably why the Buddha stayed silent.