Is there a way in OpenRoads to export drainage model to IFC?

Yes, those item types and drainage properties can be exported to IFC via iTwins.

Are properties information also exported to IFC from an iTwin. For example, I attach an item which contains properties that I created on Water Conduits, will those information be exported to IFC aswell?

You can export Drainage and Utilties to IFC from an iTwin now. The ability to export it from the desktop app is something that we are looking into.

Are there any plans to add IFC export for anything other than corridors?

That IFC export function is working for "corridor" only. We were told to use iTwin Synchronizer or https://review.itwin.bentley.com/.

https://communities.bentley.com/products/digital-twin-cloud-services/itwin-services/w/synchronization-wiki/56092/itwin-portal-ifc-exports

Hope it helps.