Are you using the app?
crazyhouse

I know you can't do variants on the app (AFAIK) so when I want a variant I'm using the website https://www.chess.com/variants

I'm not sure then. If you are using the website, you should be able to play Crazyhouse.
If you are sure that you are unable to play Crazyhouse, maybe contact support?

Because I have been forgetting about this post, I sent you a friend request. We can temporarily be friends and I will remember to challenge you.
When I go to custom game it only offers two "setups": Standard and Chest960.
Can you give more details? THanks.