Kishi changed the color to make Sasuke's eye look different. I believe Sasuke can shift from 6 tomoe to 9 tomoe. Just like he can shift from rinnegan without tomoe to 6 tomoe.
His represents the juubi's eyes while Naruto represents the body.
No. Sasukes Rinnegan is fused with his Sharingan to allow use of all his Mangekyou abilities. If he had two Rinnegan he probably would lose Blaze Release:Kagutsuchi, his special attack. Databook and Manga also call it a Rinnegan.
When his eye turns red holla back at me. But even Obito and Shin can open portals and use S/T. Do they have jubi sharingan?
Sasuke represents the eyes of the Sage of the 6 paths and Naruto, the body of the sage, not the Juubi.
Sasuke represents the eyes of the sage while he's JUUBI JIN.
Naruto represents body of sage while he's JUUBI JIN.
That makes more sense IMO.