I always felt that Maru didn't really care about Kiru's gender and rather enjoyed her as a person. He's probably just surprised by this plot twist as much as we are, as he's never considered his orientation and stuff. Understandable too, he's just 15.
I'm with Kiru about the plantation too. They were all nice, but I felt something sus about this whole operation. For the moment (before they started talking), when I was the "head" I thought "hey, is this some manson-ish cult structure?". I wonder if we're ever gonna find out what's underneath "the apparent".