Yes.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
I'd analyse it as a composite noun phrase comprised of two separate words, both nouns, where the head (main word) "bus" is modified by "school".
Compound nouns are invariably single words (sometimes hyphenated) like "beehive, "blackbird" "palm-tree", "pillow-case" etc.