In Sal Jiang's tweet about this chapter, she also (cheekily) raises questions of whether Moon is a man or a woman. The confusion seems intentional, and maybe it's not supposed to be clear yet. I didn't consider that maybe even the witches who sent them on this hunt were mistakenly thinking Moon was a woman, too (which would explain chapter 6's list). So it could go either way. It should be a fun chapter next, as always.
My assumption right now is that Moon is only playing up the "Prince" persona to lure Hanako in, and does this regularly (either as a witch for some kind of nefarious spellcasting purpose, or just as a player getting with girls). Whether this is just a persona for convenience, Moon is just crossdressing for fun, or if there's some kind of transgender commentary to come seems up in the air, though.