Hi
You'll need to reinstall Evernote first. If you don't have the file, get another via the Evernote download page.
When installed in the Applications folder, open Evernote. Then, go to the Evernote Menu and open Preferences. In the Clipping panel, uncheck the Safari option. Close Evernote.
Restart Safari. The icon ought to be gone.
To remove Evernote completely from your system, via the Finder, drag Evernote from the Applications folder to your trash. Also, in your User Account>Library>Applications Support, drag the Evernote folder to the trash. Finally, in Your User Account>Library>Preferences folder, trash the
com.evernote.Evernote.plist file.
Empty the trash.