Under 14 sim can they access their own dashboard?

Hi. Just set up my son with a new phone and wondered if on an under 14 sim can they access their own dashboard to check their usage and data etc?

I’ve tried a few times as obviously I can see it in my dashboard as family account holder but can’t seem to get it sorted their own phone and wondered if it was because it’s an under 14 sim? 
Thanks in advance 👍🏼