My kid's 9 and has had a cell phone for about a year. She can pick up most phones and figure them out in short order and she's an ace on my iPhone. Her phone is a "pay as you go" flip model from Samsung. I spend about $10 a month on minutes.
Great for emergencies, learning phone etiquette and honing her machine manipulation skillz in the computer age.
I don't see what's wrong with kids having cell phones. I got to use a phone when a was I kid, only that phone was wired to the wall. The units are cheap and basically disposable; just work out a way for them to earn minutes and not be obnoxious in public on the phone. Heck, kids don't need to a phone to do that.
Funny aside: we use cell phones for 100% of our phone calls, but do have a land-line because of of DSL/network services. The other day I had to teach her how to use our land-line! She entered the number in first then tried to press the "call/on" button. I had to show her how to get a dial-tone first
then enter the number!
I'm glad she has this "knowledge" now, in case f emergency.
FWIW.