I have sensory issues. Most of the time, I'm fine with it. The only problem comes with night nursing, especially if I'm really tired. Is there something I can do about this? Could I try to wean him a little at night and try to encourage self-soothing?

at 9 months he really is too young to night wean.
but you might try sidecarring a cosleeper or crib next to your bed so you can still wake and hear him and reach over to get him to nurse, but then get your own space back so you arent sooo touched out all the time.
i have some sensory issues as well, and if i have had a whiney clingy baby nursing on me ALL day i just want a break at night. thankfully now at 12.5 mo she can sleep longer stretches between feeds at night.
but really he is still needing that nutrition, AND the comfort.