nine vs IX

nine and IX both are nouns.

Word	Noun	Adjective	Verb	Adverb
nine	Yes	Yes	No	No
IX	Yes	No	No	No

As nouns, nine and IX are synonyms defined as:

Other synonyms of nine include 9, ennead, Nina from Carolina, niner.

nine (noun)	IX (noun)
one of four playing cards in a deck with nine pips on the face	the cardinal number that is the sum of eight and one
a team of professional baseball players who play and travel together
the cardinal number that is the sum of eight and one

nine (adjective)	IX (adjective)
denoting a quantity consisting of one more than eight and one less than ten