I assume different school system has different rules, but here in Sweden there are laws that school must adapt based on the need of the child. A disabled child should get the right tools based on their needs, which will depend on the exact circumstances.

For someone with impaired motor control skills I would assume that default software and a touchscreen is far from usable. There is a reason why many touchscreen system has a stylus pen, which would obviously not work in kindergarten for children with impaired motor control skills. A large screen and software designed for it could be one way, but I have also seen massive trackballs that I recall is being used in those situations.

ChromeOS is touch friendly, and there are several really good and inexpensive Chromebooks with 180 degree hinges for a tablet-like form factor.