You haven’t to do anything on Ubuntu machine, you have just to configure a nat/port mapping on the router connected to internet.
Let’s assume your Ubuntu machine has an internal address of 192.168.1.10
You have to tell to your router to call the 192.168.1.10 address when he receives request on your Internet address on port 9092 using the same port.
Or you can configure another port e.g. port 80 (the standard http one) and tell you router to call address 192.168.1.10 on port 9092 when he receives call on Internet address port 80.
This is the most basic configuration that assume you have just a Internet address available with the minimal hardware required. Anyway it’s not exactly the best config
Here an example of config on a basic adsl router
The first port is the one for the Internet address the second is the destination (the translation from Italian is “use the same port of source”)