A few points about 6 year olds.
If they see one kid has something then in their head, it can be the whole class.
Your kid doesn’t need a phone until the school says he needs one.
If my kid were going home on the school bus, I would give my kid a phone even though shes only 6. I would even give my 3 year old a phone if he was going home on the school bus. But that’s just because I’m neurotic and not something you should do if you dont want to.