preteen vs juvenile

preteen and juvenile both are nouns.

Word	Noun	Adjective	Verb	Adverb
preteen	Yes	Yes	No	No
juvenile	Yes	Yes	No	No

As nouns, juvenile is a hypernym of preteen; that is, juvenile is a word with a broader meaning than preteen:

preteen: a preadolescent boy or girl (usually between 9 and 12 years of age)
juvenile: a young person, not fully developed

Other hypernyms of preteen include juvenile person.

preteen (noun)	juvenile (noun)
a preadolescent boy or girl (usually between 9 and 12 years of age)	a young person, not fully developed

preteen (adjective)	juvenile (adjective)
of or relating to or designed for children between the ages of 9 and 12	of or relating to or characteristic of or appropriate for children or young people
	displaying or suggesting a lack of maturity