"It's so massive that even at an insane distance, this Oort Cloud body can out-twist the masses of both Jupiter AND Saturn."
Wait? How massive is it? How is it able to tilt the axis of the sun, since tilting an axis is a TIDAL action? IMHO (as a degreed rocket scientist) that Occam's Razor would indicate that it's easier to shift the orbital planes of the planets, rather than tidally torque the sun. Remember, for the tidal action, the Planet IX must be very close to Sol to work its magic.