I'm a new 1Password user and recently tried to export all my passwords saved in iCloud Keychain to import them in 1Password. Unfortunately, none of the existing recipes worked for me, because moving the saved passwords from iCloud Keychain to a local keychain seems to be broken as of today (28 Aug 2018). So I came up with a different method.
This method works entirely using AppleScript, and only for website passwords (not for other kinds of logins such as file servers, etc.). Basically, the script toggles back and forth between Safari's Preferences window and TextEdit, copying each username and password combination via the clipboard.