There’s all kinds of silly names they could borrow from stories hypothesizing its existence. Nemesis, Nibiru, Vulcan, and Planet X, just for starters. But in all likelihood it will end up as something much more anodyne.
Sure, I'm OK with naming it Le Creuset.
Oh, you meant anodyne ....
I think the IAU will only accept names from Mythology.
They extended naming conventions to other cultures already - IIRC Roman and Greek sources were "drying off"
There's a region on Pluto provisionally named after Cthulhu, citing Lovecraft as "an underworld mythology". If the IAU accepts the name, it would make this possible too.