Few Questions I will like to get you own input on
Is buying Bitcoin or cryptocurrency good for Kids?
Yes, as long as it is in the control of an adult. By kids I want to believe you mean 0-18 years old. When they come of age, the the custody of the bitcoin like key phrase can be revealed or released to the kids
How do you teach a kid to secure Bitcoin incase you are not there?
This is pretty straightforward. Just as I learned to secure my bitcoin. It is not rocket science.
Should authorities or agencies place age restriction on owning Bitcoin?
Can't and won't happen. If they do it so it defeats the principle of decentralization - control in the hands of the people not any central agency
Furthermore, parents should first teach their kids financial literacy. Which includes, the history of money, savings, investments, budgeting, etc. When the kids get a good hold of this, then they can proceed to teach them about bitcoin