I'm looking to use corridor designer, a tool for building wildlife corridors, but i has not been updates since the 9. something, while I have ArcGIS Pro 2, will the tool still work?
No, an ArcGIS v9 script will not work in ArcGIS Pro. Pro uses Python 3.5 and ArcGIS uses Python 2.7 so things like print statements will not work. Furthermore, your scripts are relying on the old geoprocessor library. Here is a link for more information.