Death Knight Tier 9 gear is easily obtainable now with Justice Points for the 232 ilvl. It is sold by vendors at the Argent Tournament Grounds in Icecrown. This tier was different that the look changed based on faction, rather than ilevel. So each class had a Horde and an Alliance version. Death Knights had a dps and a tanking set, but both looked identical.
Trophy of the Crusade:
These pieces are still upgradeable via Trophy of the Crusade that drops in 25M Trial of the Crusader. But the look doesn’t when upgraded.
Legs and gloves of this tier also drop from Koralon the Flame Watcher