4.9 currently focuses on notification methods for magnification users, but uses general "AT" in the requirement. 4.10 then specifically calls out announcing UI updates for screen reader users.

I wonder if these could be combined to provide guidance for announcements and updates geared toward people with visual disabilities as a whole, with a focus on audio and/or haptic feedback. That feedback would presumably be provided regardless of the way the user is interacting (gestural or not).