We've done Star Wars three times and Wreck it Ralph once with another planned in Feb. We love the experience and have fun as a family team of 3. We started doing this in Feb 2018 as it was our son's 10 birthday and have done it in FL and CA. Both are really fun, but we wanted to do WiR again this time. SW is more intense and Ralph is "cute" but both involve lots of shooting and teamwork.
They didn't "card" him, but we didn't try to break the rules either. Our son is tall for his age and could have probably gotten in at 9, but we aren't the type to try. Ralph would be easy to handle for most any age, but as others noted, the equipment would be heavy for smaller children and could be a safety hazard if they had issues. There's lots of moving around and listening for direction, so it could be hard for some (including adults...).
Mike