Quit all Adobe Applications (Illustrator, Lightroom, Photoshop)
Open Creative Cloud App
Go to Help, located on the top bar of the computer
Select Sign out
Close the Adobe CC App
Next open Safari
and Select Clear History
All History
Quit Safari, don't just close the app
Then reopen safari and go to Adobe.com, it should prompt you log in, that's how you will know you are logged out