So I tried searching for a thread on this but the search engine doesn't quite work when you type in XX-9.

If I have XX-9s and I only do enough damage for one critical does that still negate contain?

Contain does not prevent XX-9. Doesn't matter if it's one card or two.

7 hours ago, TallGiraffe said:

So I tried searching for a thread on this but the search engine doesn't quite work when you type in XX-9.

If I have XX-9s and I only do enough damage for one critical does that still negate contain?

I think I get where is the issue of your question.

Long Answer: Note that xx9 is a special crit. special crits bypass contains(unless dco). xx9 is "first 2 damage cards dealt face up". Even if you deliver only one damage card this attack it is one of the first 2 damage cards, so it is dealt faceup(still under xx9, still a special crit, still bypass contain). Dealing only one damage card does not revert it back to a normal crit(which contain can block) one of the benefits of taking xx9

Note: you must still have an uncancelled crit face present in dice pool