Yes, you would need to set the Source Translate under the advanced settings for the policy. This will translate the traffic from 192.168.55.0 to the IP of eth0/9. 192.168.x.x are private networks and are not allowed to be routed across the internet. As such, you must translate the traffic to a public IP address. This is what that setting does.
Again, I apologize if any of this sounds stupid or I am making a mockery of it all... really out of my element and greatly appreciate the help!
Not at all. This is how you learn. We were all in your situation at one time. 
If this doesn't work, try the following debug to see how the traffic is being handled.
https://kb.juniper.net/InfoCenter/index?page=content&id=KB23844&actp=search#basicdebug