Diablo III Season 9 Details

Battle.net offers a first look at what to expect from Diablo III Season 9, which gets underway in under two weeks on January 6th. They update the various challenges and rewards this will entail, including a new Class Set available through Haedrig's Gift for completing certain chapters in the Season Journey. They also explain that they are going to save on hard drive space by deleting older seasonal records. Here's the explanation of that:
As we continue on into additional Seasons, we will no longer be able to store some personal Seasonal records. While Season 9 will store your personal bests for all Seasons to date, at some point in a future Season we will begin removing old personal bests, beginning with Season 1. This will be true regardless of your participation in past Seasons. We will have more details on this at a later date.

Seasonal Leaderboard records are not being cleared, and will remain archived both in game and on our website.