Reinforce your drywall and keep an eye out for peeping RC cars - Rainbow Six Siege is coming on October 13. And yes, there will be a Season Pass.
Ubisoft didn't say what the pass will actually include (my guess is at least a few more Operators on top of the standard 20) but you can pre-order Rainbow Six Siege Gold Edition if you're already sure you want it.
If you're in Europe and are really really sure you already love Rainbow Six: Siege, you can even pre-order the Art of Siege Edition, which includes the game, gold skins for of its weapons, a 120-page guide, and a "collector's box", or the Tactical Elite Edition, which bundles all that and the Season Pass. Only the base and Gold editions have been confirmed for the Americas at this point.
All pre-orders will be rewarded with guaranteed access to the beta later this year. Ubisoft apparently made some pretty significant changes based on feedback from Siege's brief closed alpha last month, so it should be interesting to see how the beta version differs.