This is not a close case.
You could make various policy and doctrinal arguments as to whether the police should be able to search a home without a warrant (and not get the resulting evidence suppressed) merely because the person they were investigating was -- with the co-occupant's consent -- living there in violation of a no-contact order. For example, personally I'm a fan of warrants before the police invade a home.
But there's a ton of precedent that makes it clear that you don't have standing to challenge a search when you're not permitted to be there. (For example, you're a trespasser.) From the reasoning of those cases, it's fairly clear that you don't have standing to contest a search in cases like the one here.
So right or wrong, that's what the law presently entails. Hence the Ninth Circuit's correct holding today.