Alright, speculations are over now :) Blizzard have preliminary published the press-release for 9.1.: Chains of Domination. Here goes:
The traitorous Sire Denathrius has been defeated . . . but the power of the Maw still grows. In Chains of Domination™, the upcoming first major content update for World of Warcraft®: Shadowlands, players will delve into new depths of the Jailer’s hopeless domain, seeking to understand the true nature of his malignant plans. Backed by the renewed might of the four Covenants, the champions of the Horde and the Alliance will take the fight for the Shadowlands to the seat of the Jailer’s power. But the Banished One has a terrible new champion in his service—a cruel instrument of despair conscripted by Sylvanas Windrunner, capable of instilling dread into the hearts of Azeroth’s heroes like no creature of the Shadowlands.
Discover the Mysteries of Korthia – The Jailer is searching for the key to fulfill his twisted designs—and he has pulled a fragment of a long-lost domain into the Maw itself to find it. Seek answers in ancient Korthia, the City of Secrets, and engage in new quests and outdoor activities.
The Covenants Strike Back – With the strength of the kyrian, night fae, necrolords, and venthyr restored, embark on a campaign to unite the four covenants—and together, launch an assault against the Jailer in his home territory.
Raid the Sanctum of Domination – Brave treacherous, unexplored reaches of Torghast in a new 10-boss raid: the Sanctum of Domination. Encounter the true Eye of the Jailer, turn the tide against the Tarragrue, and come face-to-face with the Banshee Queen herself in a fateful confrontation.
New Mega-dungeon – Tazavesh, the Veiled Market—Gather your party and discover exotic wares and strange creatures in an eight-boss Mythic mega-dungeon set in a bazaar of the mysterious Brokers, and culminating in a high-stakes heist to steal powerful artifacts from Azeroth.
And More – Gear up for Shadowlands Raid, Dungeon, and PvP Season 2, with a seasonal Mythic Keystone dungeon affix themed around the Jailer’s power; don new Covenant cosmetic armor sets that any class can wear; expand the powers of your Soulbinds and Conduits; add new mounts and pets to your menagerie; Unlock flying in the Covenants’ four domains; and much more.
Torghast raid: too soon?