I have both Google Chrome and Vivaldi installed, and I don't see any indication of CCleaner cleaning anything from a Vivaldi folder when I select analyze/clean from the Google Chrome results, should it say something specific about Vivaldi?
I have:
Windows 10 Home Edition (64-bit)
Vivaldi v1.2.490.43 () (32-bit)
Google Chrome v51.0.2704.106 m (64-bit)
CCleaner v5.20.5668 (64-bit) portable build, run from hard drive
Since it's cleaning the Extension State and Session Storage make sure your extensions are working properly and are remembering your preferred settings such as adblocking software still having subscriptions, etc., and any other extensions that can be configured.
As I posted in “Vivaldi Speed Dials”, CCleaner handles other derivative browsers such as Vivaldi as Google chrome. The user data of other derivative browsers are detected and deleted as Google browser even the lacations of other browser.
As I posted in “Vivaldi Speed Dials”, CCleaner deletes jumplist (maybe related to speed dial) and then the speed dials are also deleted!
I usually use Avant Browser (http://www.avantbrowser.com/) and it has Chrome engine inside, and the user data are cleared by CCleaner.
I think CCleaner should handle the derivative chrome browsers as separate browser, and do not clear the other derivative browsers!