Based on Kevin Delfour's excellent kdelfour/cloud9-docker image, this version includes a docker-compose setup and various improvements (e.g. usage of nginx-proxy reserve proxy setup).
This image requires a properly set up nginx reverse proxy Docker container as provided by jwilder/nginx-proxy.
Get the egoexpress/cloud9 container from Docker Hub or build it yourself using docker build. Afterwards, set DOCKER_CLOUD9_HOSTNAME to the hostname of your choice (that is reverse proxied by nginx-proxy), DOCKER_CLOUD9_USERNAME and DOCKER_CLOUD9_PASSWORD to your user data and start the container instances using docker-compose.
docker build -t egoexpress/cloud9 .
export DOCKER_CLOUD9_HOSTNAME=cloud9.example.com
export DOCKER_CLOUD9_USERNAME=johndoe
export DOCKER_CLOUD9_PASSWORD=foobar
docker-compose up -d
Then use your browser to go to http://cloud9.example.com (the host your specified in DOCKER_CLOUD9_HOSTNAME) and login.