A few things to note here. It appears that you are using the URL of your Jive instance in your jiveclientconfiguration.json - Definition as your clientUrl, when in fact it needs to be the URL for the host running the Jive SDK service. Your jiveon trial doesn't have anything running on port 8090 for sure.
Make sure to change the clientUrl in your jiveclientconfiguration.json to be the public resolvable hostname for your server, re-run node app.js and upload the resulting extension.zip file to your jiveon trial.
Hope that helps.
Yep. You must make sure that bidirectional communicationb etween your jiveon instance and nodejs service host is possible. See From Zero to Cloud Service in 20 minutes using the Jive SDK and Heroku for an example of hosting your service on heroku for free, as quick and simple way to get started.