There is a video available for Rational Application Developer (RAD) that assists you with downloading installation files. The concept of the video is based on parts of the Rational Application Developer for WebSphere Software 9.0 download document. There are many listed when looking at RAD 9.0 on Passport Advantage. The video provides an overview of what is available in the list of files and what you download depending on your usage of RAD.
Rational Application Developer
Author: Leila Ezeddin
Thank you to Leila for her work on this video!
Here is a look at the YouTube version of the video in case you want to preview it here: