https://wccftech.com/world-of-warcraft-shadowlands-pre-patch-9-0-1-download/

While the release of the World of Warcraft Shadowlands Pre-patch has yet to be confirmed, the data files can already be downloaded through Blizzard’s background downloader.

With the Shadowlands expansion hitting retail servers next month on October 27th, the Shadowlands Pre-patch 9.0.1 is expected to become available later this month. As reported by World of Warcraft news site Icy Veins, Blizzard has yet to provide a 2-week notice for the end of the current World of Warcraft expansion, Battle for Azeroth, but on the World of Warcraft Reddit, several players have seemingly already downloaded the upcoming update ahead of the launch of the pre-patch. Based on these reports, the arrival of the pre-patch content is imminent and Blizzard will likely announce its arrival shortly.