rapture vs cloud nine

rapture and cloud nine both are nouns.

Word	Noun	Adjective	Verb	Adverb
rapture	Yes	No	No	No
cloud nine	Yes	No	No	No

As nouns, cloud nine is a hypernym of rapture; that is, cloud nine is a word with a broader meaning than rapture:

Other hypernyms of rapture include bliss, blissfulness, seventh heaven, walking on air.

rapture (noun)	cloud nine (noun)
a state of being carried away by overwhelming emotion	a state of extreme happiness
a state of elated bliss