Nostalgia is not Science.

Nostalgia is not Science.

TL;DR:
We either recognize 8 Planets and 100s of Dwarf Planets OR 100s of Planets.
Making an exception for just Pluto is based on Nostalgia and "Feels", not science.

Post:
If "well, I was told in school." is all you care about; welcome to Class:

Pluto (Discovered 18 February 1930) is approximately 0.218% Earth's Mass with a 715.2 mile radius.
Eris (Discovered 5 January 2005) Is approximately 0.27% of the Earth's Mass with a 722.65 mile radius.
(units imperial for informal purposes)

So, If you think "Large thing = Planet, duh Obvious" consider that Triton (one of Neptune's moons) is bigger (840.96 mi) and more massive (0.359% Earths) than Pluto or Eris.

"What is a planet then, smartass?". I'll let NASA explain:
https://solarsystem.nasa.gov/planets/in-depth/

"With the discovery of the Kuiper Belt and its thousands of icy bodies (known as Kuiper Belt Objects, or KBOs; also called transneptunians), it was proposed that it is more useful to think of Pluto as the biggest KBO instead of a planet."

"Then, in 2005, a team of astronomers announced that they had found a tenth planet—it was a KBO similar in size to Pluto. People began to wonder what planethood really means. Just what is a planet, anyway? Suddenly the answer to that question didn't seem so self-evident, and, as it turns out, there are plenty of disagreements about it."

"The International Astronomical Union (IAU), a worldwide organization of astronomers, took on the challenge of classifying the newly found KBO (later named Eris). In 2006, the IAU passed a resolution that defined planet and established a new category, dwarf planet. Eris, Ceres, Pluto, and two more recently discovered KBOs named Haumea and Makemake, are the dwarf planets recognized by the IAU. There may be another 100 dwarf planets in the solar system and hundreds more in and just outside the Kuiper Belt."

Conclusion: either we currently recognize 8 Planets or 100s of Planets -- not 9.
At least until more discoveries are made. Because THAT is how science works.

Sincerely,
A Snobby Asshole

PS. Use or twist how you see fit.
"You know, the very powerful and the very stupid have one thing in common: they don't alter their views to fit the facts; they alter the facts to fit their views." -- Chris Boucher, writer for Doctor Who?