Oddly enough, Aliens are not overly common on this site. That said, this idea has major issues that are not related to originality. For one thing, how could aliens as intelligent as cats travel to earth? Inter-dimensional beings or just cryptids might work better here, as aliens are mentally associated with extraterrestrial intelligence. Unless these things are alien pets? That could actually be an amusing idea to explore, perhaps with the aliens taking them back and leaving a thank you message for caring for them in their absence or something like that.
Kinda relates to what I just said, but you need to choose a narrative direction and themes to explore with the article or it will feel bland. You could go with the lost pets suggestion, or another of your choosing.