I think I know the answer, but... Can I bake it in a 8-inch round pan?

Well- you could likely get away with it if your pan is deep enough; A 9" pan is about 1 1/4 the area of an 8", and the cake will be commensurately deeper, so will take longer to cook, may come out somewhat denser because of the added weight on it's own structure, and also may come out a bit drier because of longer cooking time. It's likely doable, but you'll have to find your own way to a certain extent- unless someone else has actually done it.