Every Disney resort has kids, everywhere. Hundreds of kids. At the moderates, probably thousands. Theoretically, it seems that a convention resort should have fewer kids around and about, but in practice, I'm not sure you'd be able to tell the difference. I've never been able to.
It doesn't matter if the kids are in school or not. People bring preschool kids, and people take kids out of school.
If you want a noticeably smaller amount of children, I'm afraid you're going to have to look offsite, particularly at the higher-end resorts like the Ritz-Carlton and the Waldorf. The Waldorf is probably the closest resort that would suit your needs, and there've reportedly been some really good rates offered there. I think it's worth checking out.
And in all seriousness, if you're looking to see somewhat fewer children, you might want to rethink the dates. With Pop Warner going on, there will be teenage cheerleaders and football players everywhere. Cheering on the buses, and in the theme parks. And possibly at your resort, in large numbers. I wouldn't consider staying at a value or moderate during Pop Warner.