I'm in the UK, and while regular banks don't generally provide debit cards at low age, providers like Go Henry specializes in accounts for kids with built in parental controls from age 6. They are effectively prepaid visa cards with app access for parents to top up instantly.
With respect to closing accounts, there are extremely few cases where people can be denied a basic account with the largest banks, but most smaller banks are not required to provide a basic account, and other account types can be denied at will, and most people have other accounts types (there are something like 7 million basic accounts).