What qualifies it to be a planet anyway is:

1. It must NOT be a moon of any other celestial body and it must NOT be a star in itself --- it fulfills both these requirements

2. It MUST revolve around a central star in an orbit which it does.

Pluto fulfills all these conditions - it is just a dwarf sized planet, but cannot be defined as anything else but a planet. The controversy seems to still be going on.