Bring back Pluto!
Anyway, 9 is not an option, you must choose 8 or 10+.
What logical rule would you propose that allows Pluto to be a planet without also bringing in a bunch of others?
If you just want to arbitrarily declare things are they way you like them to be, religion is over there.
The rule would be: pluto is a planet, stay mad nerds
Next time you go to the grocery, grab a cucumber and a watermelon and try to find the differences.