Question "a 90's kid" - Correct translation/text representation in kanji (tattoo template)

[Omni]

Hello guys,

I'm new here and just found this great forum on my way to solve my problem and I hope you guys can help me out.
I'm planning my new tattoo and a part of it will be the expression "a 90's kid" in kanji (vertical notation). After my own web research I'm slightly uncertain because I found different text representations of it.

I really hope you guys can help me out finding the most sensible variant of it
Which of the following variants makes the most sense and has the highest credibility even for a native speaker?

1. 90年代の子供
2. 九十年代の子供
3. 1990年代の子供
4. 千九百九十年代の子供

I would like to thank everyone in advance who takes the time to help me finding the most correct spelling!
Stay healthy and best regards
Omni