re: Don't alot of southern HS football players "redshirt" in 8th/9th grade to grow & mature?

Tuscaloosa is correct, at least in my experience.

For example, I know one family who has multiple boys, all of which play/played in college (at some level). They held them back in kindergarten/elementary, which allowed them to physically mature by the time they hit high school. All the kids got full scholarships.

Contrast this with Robby Ashford at Auburn — he's been "the dude" since middle school, but as far as I know, he was never held back and just now turned 20 (like in October), despite already having three years in college (two at Oregon, one at Auburn). I think one could argue that he would've benefitted from an extra year of maturity.

I've never heard of redshirting in high school.