Hi Robert,
Re: "I have a visually-impaired and wheelchair-bound student who has difficulty seeing presentations
on the large, wall-mounted screen in the classroom.
Is there a way to get the presentations to appear on his iPad (9th Generation)
which is mounted on his wheelchair so that he can follow along during the lesson?"
Welcome to the Apple (user-to-user) Community, and thank you for posting your question to the community.
Am no expert in this area, yet your question surely deserves some reply!
Wondering. in what way you achieve the presentations on the large screen.
Eg: If you use a Mac to display the presentation on the large screen :
Apple support has an article online which may assist in accomplishing the help for your student:
(NB: Article is for MacOS Sonoma, else please choose an earlier Mac OS version at top of article for accuracy) See if you can Extend or mirror your Mac desktop across multiple displays - Apple Support
There are various ways to mirror the iPad screen to an external display, yet not so many in the other direction.
You may be able to use Sidecar to "mirror" the screens so that Mac and iPad display the same content.
See Use iPad as a second display for your Mac.
If you use the Keynote app:
See how to: Play a presentation on a separate display in Keynote on Mac - Apple Support
If you do not use a Mac:
At least this will get a discussion under way, and if you let us know more about the hardware and software you use for the lesson presentations, others with more expertise than either of us may contribute.
All the best :-)