Kindergarten teachers don't usually change diapers.
However if the Kindergarten student wears diapers then they can go to the school nurse to have their diapers changed.
The school nurse can and will change the Kindergarten students diapers.
Or if the child can change their own diaper they can go to the nurses bathroom and change their diaper there in private.
Schools will not usually accept a non potty trained child unless they have medical issues.
However the kid can still wear a diaper to school and then have it changed or get it changed by the nurse.
I remember wetting my pants in Kindergarten and the nurse put me in a plastic backed pampers diaper.
Then I wore a pair of sweatpants over the diaper and I could hear the crinkle of the thick plastic backed pampers.
It felt so good to wear the diaper though and I had to wear Pampers diapers for the rest of the Kindergarten class year because I wet the diaper all the time on purpose to stay in them.
It was easier and better to just use the diaper instead of having to go to the toilet.