If you can manage somehow to get the Icarus registered with your AdobeID, you can try 'sideloading'; that is copying books from the PC onto the Icarus directly using a file manager. However, you proably won't be able to register it if you can't get ADE to recognize it.
For DRM books, you will still need ADE to process the .acsm files and download the DRM .epub files. Then copy the .epub files using file manager rather than ADE.
For non-DRM books there is not need to use ADE in any case, and no need to register an AdobeID on the Icarus; just copy the books to the Icarus.