You can get Photoshop CS6, CC, and CC 2014 all from the Creative Cloud application.
But I HIGHLY doubt that files that Photoshop CS6 can open would not be compatible with Photoshop CC. Photoshop CC is, when you brush away the clouds, just an evolution of the product that's being licensed a different way. All appearances are it's compatible with files made before.
I know nothing about Adobe Illustrator.
-Noel
