Yes, for the schools you mention, it’s worth sending interest emails to the coaches-and in those emails, detail his progress the way you have here, with an emphasis on the clear upside your son has. I’d recommend mentioning both T&F and XC as interests.
And good 400/800s are tough to find-so keep working on that. With his academics and the obvious upward trend in athletics, I think you’ll be pleasantly surprised-good luck!