I do not see a point in it either really. The game is bigger on Switch than it was on WiiU, it may as well just be considered a major Switch exclusive at this point. The only reason I would see them bringing MK9 to Switch is as a trump card if sales slow, but I still think they have a bigher idea for it.
Imagine if the Switch 2 had MK9 as an exclusive during its launch window.
That's exactly what will happen. MK8D will continue to be one of the best selling Switch games each and every year it's on the market and will likely go on to sell over 25 million, making it the 2nd best selling game in the franchise.
When the herd loses its way, the shepard must kill the bull that leads them astray.