The version 18.9.1 of VCDS is a relatively old version of the software. The download process for this version is no longer officially supported by the developer, Ross-Tech, LLC.

If you're looking to use the latest features and improvements, I recommend downloading the latest version of VCDS from the official Ross-Tech website. The current version is 20.4.0 (as of April 2022).

You're looking for a complete report on "VCDS 18.9.1 download". Here's what I found: