Should be.
I don't think it's anything to do with permissions: there's nothing in them that relates to app icon badges. However if you look in the app's notification settings (in Settings > Apps > WhatsApp rather than in-app) there should be a switch for "app icon badges". Maybe check your launcher's settings if that doesn't work.
(For the record I allow WhatsApp the permissions I think it needs for sending and receiving calls and messages and sending media, i.e. I allow it camera, contacts, files & media, microphone and phone. I do not allow it access to call logs, location or SMS. But as I say, there's nothing in that list that is relevant. If I look at the full list of permissions there is also "read badge notifications", but that's not one that's user-controllable).