I don't have anything special saved for my 9000th achievement. Going to have to be something mundane.
Double XP and premium subscription benefits for all during Halloween weekend. The game itself, or at least the console version, is free for that period.
A true Pirate Legend is one of the greats and for them, Athena's Fortune awaits… - Sea of Thieves
A peg-leg, an eyepatch, a hat and a hook, all purchased to pull off the true pirate look! - Sea of Thieves
Sun-bleached skulls from across the ocean earn the Order's highest Promotion! - Sea of Thieves