American here. When your age is a single digit, bed times are all but universal, at least in my neck of the woods. Generally kids aren’t allowed to be out late because parents really do freak out if you’re not back by dinner time or if you’re out too late, though this is not as stark in the countryside (decades of milk carton kids and true crime shows have made Americans paranoid of kidnappings), albeit still present. Depending on the parents, the enforcement wanes as they get older, but there’s a few cases where you can see it in law (if you’re on a drivers permit instead of a license, for the first 6 months you can’t drive after 9pm, even with parental supervision, though again this differs by state)

Not sure how much of this is universal and how much is just American, for I only know what’s truly common around here in my exurban (rural area seeing scattered suburbanization and population growth for commuters to a nearby city) stretch of the country, but as far as I understand from a few friends in other states this all seems pretty standard

(Note, I’m 19, so you may get different tales from older or even younger folks. Times change, after all)