It was determined as recently as 2010 that Pluto does not qualify as a true planet due to its gaseous mass formation, illegitimate shape, and irregular orbit. We are back to eight planets until final confirmation of Planet X as the true ninth planet.
Pluto's orbit is longer and slower than other planets.
Pluto is different from the inner planets in that it has not cleared it's orbit from asteroids.
None of the eight planets has an orbit that crossesanother. Dwarf planets (which include Pluto) and Dwarf Planet candidates do cross orbits of planets and each
Pluto does not have an orbit clear of asteroids and debris. Planets do.
Pluto's orbit passes inside the orbit of Neptune.
Pluto is farther from the Sun than the eight planets. It takes 248 years to complete one orbit. This means that one year on Pluto equals 248 Earth years.
Pluto is a dwarf planet. It is smaller than the other planets. It also has a very irregular orbit.
Pluto is smaller than any of the eight planets. Also, it hasn't "cleared its surroundings" - I guess that basically this means that it is not the dominant object in the surroundings of its orbit.
Pluto's orbit is quite unusual. It takes 248 Earth years for Pluto to complete one orbit around the Sun. Its orbit is also more oval-shaped, or elliptical, than those of the 8 major planets. That means that sometimes Pluto is a lot nearer to the Sun than at other times, At times Pluto's orbit brings it closer to the Sun than Neptune.
Pluto, and all of the planets orbit the sun. Not the other way around.
1. Pluto doesn't orbit the same way as the other planets in a horizontal orbit it has a diagonal orbit
The minor planet Pluto has an orbit which is inclined to the plane of the ecliptic. It is also a highly eccentric ellipse, causing it sometimes to pass inside the orbit of Neptune.