You can use a Rule to add the metadata as custom claim to the user info. Code in the rule would be something like this:
context.idToken['http://somenamespace/user_metadata'] = user.user_metadata;
Also see
You can use a Rule to add the metadata as custom claim to the user info. Code in the rule would be something like this:
context.idToken['http://somenamespace/user_metadata'] = user.user_metadata;
Also see