As much as I love this relationship, it’s still counted as paedophilic.
Well, I'm not sure they have mutual feelings tfor each other. I doubt what demon-chan feels for exorcist-san is love (crush/like or admiration, maybe) and more so for the latter. At this point I think the guy's just courteous and doesn't think about things like that (or maybe that's just me).
And I like to think that what's happening between them right now is just deepening of relationship (not to be taken as romantic) of two people who are lonely and wants company.
Already hating the male lead but hope there would be a good character development soon.