she doesn't have a badge, the Marisa, clearly have a badge, so no, no pet, maybe she was an invader that, like tewi, wanted to do the "dominance declaration" but the Marisa cockblocked it, and through that very act, killed any dominance intention the tewi may had after doing her own declaration before.
Of course i do wonder why the Tewi doesn't have a badge if it is a pet as well, since Marisa clearly has it, yet neither her or Reimu have it, so i wonder if either they are fodder, pet in training or what, but considering how badly the Marisa hitted it, i may think the Reimu seems to be an invader that got denied the right of doing her own declaration.