Yes, you can download CS6 apps from the Download Center on creative.adobe.com. Click any app icon. From the product download page, for instance Illustrator, look for the heading "In this version" and click the version pop-up menu beneath it to select CC or CS6. The big blue Download button at the top of the page changes to "Download CS6".
Note: It is fine to have both CS6 and CC apps on your computer. Some users require mutliple versions for different clients, etc. Its a personal preference, but in no way is a requirement to uninstall your CS6 apps in order to install CC apps.
Tip: From the Creative Cloud destop app, click the "More Information" link under any app to be taken directly to the product download page.