I've recently read Mindstorms by Seymour Papert and I'm currently reading The Educated Mind by Kieran Egan. I've got a few questions about the intersection between these two and their application. Although somewhat related to developmental psychology, I'm not sure if educational theory is on topic here. If it's not on topic here, what other site should I go to?
Yes, I think that most aspects of educational theory would be on topic. In particular topics related to how people learn, how best to educate, etc. are on topic. We aim to take a scientific approach to answering such questions on this site.
There are plenty of relevant tags that might give you a flavour for what is considered on topic:
Yes all the sciences of study of cognition are welcome. Primarily we focus on psychology but every once in a while someone asks an anthropology or sociology question. Some psychology counseling departments are found away from the psych department itself in education. I think that shows a bias toward cognitive behavioral therapy form of behavioralism rather than even allowing analytic perspective which is sad but it happens. Education has a similar relationship with the other social sciences as physics and math share.