no, 在.....里面 means among, this is Among these building = 它在这些楼房里面

First of all, "八楼" mean "eight floor" ; "九楼" mean "nine floor". "two building" should be "两栋楼" For your question, "之间" use as "Among". e.g. it Among these building. = 它在這些樓房之間。

Hi, I used to say 那个在八楼和九楼之间。That locates between eight floor and nine floor. if I word 那个在八楼和九楼中间。That locates at the middle of eight floor and nine floor. Do you make sense? 中间 at middle of, intermediate. 中( middle)间(places)。 Otherwise, the post office is between the bank and theater. there is bank, next is post office, and the theater is at the third building. then we say 邮局是在银行和剧院 的中间。或者邮局是在银行和剧院之间。Both are the same. My opinion is the chinese language's spacious idea is very strong. just personally. let other people correct me if I am wrong.