cloud nine vs bliss

cloud nine and bliss both are nouns.

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

As nouns, cloud nine and bliss are synonyms defined as:

Other synonyms of cloud nine include blissfulness, seventh heaven, walking on air.

cloud nine (noun)	bliss (noun)
a state of extreme happiness	a state of extreme happiness