There aren't really any bus depot objects kicking around, so you'll need to make your own if you want an object.
Alternatively, you can utilise smaller buildings, and use your imagination to make them into a depot. There's a maintenance workshop in one of the UKDT folders, although I couldn't tell you which, but you can find it by loading up BotW 2.9 in the editor at the depot, clicking the object and reading the red writing at the top of the screen which tells you where the scenery object is located.