Can kids enable Apple Cash on their iPhones?

See the following from Manage your Apple Cash account - Apple Support

In order to send and receive money with Apple Pay or receive the Apple Cash card, you must be 18 years old and a resident of the United States.

According to: Send, receive, and request money with Apple Pay - Apple Support

"To send and receive money with Apple Pay, you must be at least 18 years old and a resident of the United States."