ssh -L 3301:localhost:3301 -l cloud9 cloud9
or
ssh -L 3301:localhost:3301 cloud9@cloud9
This will allow you to connect locally to port 3301 to your instance which is running on cloud9 instance with is also on 3301.
https://serverfault.com/questions/597765/how-to-connect-to-mongodb-server-via-ssh-tunnel