New evidence points toward Ninth Planet in the solar system

[Anomalocaris]

That's true; but I specifically stipluated reasons of tradition, rather than strict scientific accuracy. Basically the same sort of reason that The Plough is recognised as an entity in its own right, despite its more accurate status as an asterism of Ursa Major.

That's a name, not a classification.  A name can contain any degree of tradition desired.  A classification should be useful first.

If any plutoids similar in size to Pluto qualifies as a planet, it reduces the usefulness of the planet classification, since Pluto is really a very minor body and probably quite average for a plutoids and there could well be hundred or even thousands plutoids not far smaller than Pluto.