I stutter (severe) and my 7 yr old stutters (mild?), but he also has speech apraxia. It can be difficult to understand him as well. During Pre K and Kindergarten, he used an AAC device, which is basically a tablet with an adaptive communication app. He didnt use it all the time in Kindergarten, just when it was harder for him or they couldn't understand him. If you think that would be beneficial have a discussion with the SLP at school. The school should be able to provide tbat for him. Does he have an IEP?