ToGC (T9) Assassination Rogue "BiS" List
I've been unsuccessful in finding a T9 BiS list for Assassination Rogues on any current forum from any private server. So, I have made a tenable BiS list here. I'm sure there will be some disagreement from some people. If you do, please open a constructive dialogue!
Here is an AtlasLoot picture of where to get each item, since the names change slightly between factions, and links for each item.
https://i.ibb.co/VCHDNK1/To-GC-T9-As...-Bi-S-list.png
Head: Garona's Helmet of Triumph
Necklace: Charge of the Eredar
Shoulder: Shoulderpads of the Snow Bandit
Cloak*: Sylvanas' Cunning or Vereesa's Dexterity
Chest: Vest of Calamitous Fate
Wrists*: Solar Bindings
Hands: Garona's Gauntlets of Triumph
Waist: Belt of the Pitiless Killer
Legs: Legwraps of the Broken Beast
Feet: Acidmaw Treads
Ring: Band of Callous Aggression
Ring: Band of Callous Aggression
Trinket*: Comet's Trail
Trinket: Death's Choice
Main Hand: Gouge of the Frigid Heart
Offhand: Stygian Bladebreaker
Ranged*: Fezzik's Autocannon or BRK-1000
*Because some of these items may be hard to obtain (Tribute to Insanity or Algalon kills), here are a few alternatives for those items.
With the aforementioned BiS list, you should only need 1 Precise Cardinal Ruby and 1 Accurate Ametrine. All other gems (20), with the exception of 1 Nightmare Tear, can be Bright Cardinal Rubies regardless of socket color classification.
Some of you may be thinking that it isn't a good idea to forgo the 4-set since one may arguably have an easier time getting it as well as the perk isn't terrible (5% increased critical strike on Mutilate).
In defense of choosing to ignore it, you gain 171 (102+69) haste rating from the chest and shoulders which converts to approximately 5.2% haste. The 5.2% haste after SnD and 20% melee haste becomes approximately 8.8% haste. This will further stack with Bloodlust/Heroism, Hyperspeed Accelerators, Berserking, et cetera, etc.
I hope this was of some help for some of you. Feel free to contribute other opinions, but be sure to account for any lacking hit/expertise rating as a result of your suggestion, if any.