Getting my son started in trading

I'll start with I don't know anything about trading!!! I'm an econ major. My son is 8 and he has his piggy bank money, I want to start introducing him to the idea of day trading. I remember seeing a documentary on YouTube about a high school student whose teachers during the school day with let him leave the classroom to make trades. I'm wondering if this is something if he got into an early age that he could make a lot of money in. Is it worth it? I don't know where to even begin! Does anybody have any good resources?

Thank you!