He'll have a math packet to do this summer, and that'll be enough--just spread it out over each week. Geometry and algebra overlap some, but it's very different mostly.

Given that you have a very bright kid capable of getting a 479 with pandemic-limited instruction at age 11, you might want to look at Art of Problem Solving's "Introduction to Algebra" book or their online course. AoPS targets this group.

Alternatively, Life of Fred Algebra has an interesting narrative format. Generally I don't think LoF provides enough practice to serve as a standalone curriculum, but there is a book of additional problems for that level. And extra problems might not really be all that necessary if it's a smart kid making a second pass through the material to firm up some of his weak points.

If you're looking for a more conventional textbook, then I've heard good things about Harold Jacobs' "Elementary Algebra" and (especially) older editions of Dolciani's Algebra I textbook.

Khan academy or school review packet. 480 is fine. I wouldn’t retake the course.

I got my son's Algebra I SOL score, and he only got a 479, even though he has an A in the class. What can we do to reinforce these concepts with him over the summer, so that he is definitely ready for Geometry? Are there books or online programs that would be good? DH and I are not math people.

DH thinks that maybe my son should redo the course, since he has plenty of time to progress through the math curriculum (he skipped a grade, and is only 11, almost 12), but that seems unnecessary to me under the circumstances.