My 6th grader is in our local gifted public school class and will take Algebra I next year in the junior high for 7th grade (well, it's now called Common Core 2/3, but it was Algebra I).
My question is how to help him for next year.
In the summer, he will take classes at our local community college, which has accelerated classes for children. It will be his third summer doing it, and they are a lot of fun. He really likes it.
The question is this- should he take over the summer the class they have for Algebra I, which actually gives you high school credit? Or take Pre-Algebra?
At first, I thought pre-algebra but I think he knows it well and he could be bored. Any thoughts? Thanks!

If you have confidence that he knows the prealgebra, and it sounds like you do, then there is no point sitting through a summer class.

Are there any implications for him in taking the Algebra 1 class? Does it cover everything and therefore potentially make sitting through it in year 7 tedious? Or is it a taster course which will kickstart his progress in yr 7?

If it is a comprehensive course can he then test out of Algebra 1 at school and do something else?

Sorry just re read the bit that says the class will give High School credit. In that case what would the school say? Are they happy to accept the credit and give him a different class at school?

Would it be possible for him to take some interesting math, like discrete math or problem solving? I am thinking that if he already took a GT Pre-Algebra course this school year, there is no point in repeating it over the summer. I am also thinking that it may be equally painful to have to cover an Algebra I course twice, especially back-to-back. In my experience, high ability students don't need extra repetition as even once sometimes seem too much.

I would suggest buying the Introduction to Number Theory book (and answers) from the Art of Problem Solving and letting him spend some time on this book over the summer.