I have been hearing variations of this story, and the scientific claims for it, all my adult life.
It just could not possibly be that accepted, orthodox science regarding our solar system has any flaws in it, which if understood would explain the solar system without any necessity for a “planet nine”? No, science NEVER encounters such realities, never. /sarc
Didn’t you ever watch Planet 9 from outer space?
Longer than that.
Some of the calculations suggest a gravitational sink somewhere out there.
Some observations do to.
And to be honest, there are a lot of old legends about another planet that blows through the solar system on occasion. Nibru is the one that has become most popular these days, but Phoateon (Spelling?) was in the past.
Computer models say there must be a 9th planet then by golly it must exist, the computer models can’t be wrong. I’m sure we can’t see it because it’s being blocked by all the Dark Matter or Dark Energy or Higgs Bosons or strings that computer models also predict must exist.