A phone yes. After what happened at Sandy Hook and Columbine, my kid would NEVER be a school without one. Or any place with out one.
Most phones these days connect to the internet. Even my regular cell phone does. I never use that feature however.
It doesn’t need to be an IPhone or a “smart” phone to make calls.
I use my cell phone mostly for work-I text and make calls, and I do not have the internet enabled-if I need the internet at work, that is what a damn laptop is for.
If danger to the kid is a concern, then attach a tracking device to them-it can’t be turned into a dangerous toy...