Does anybody know if Google expose the new 'Popular times' information in the places API? and if not is there another API I can use to get a locations popularity?
As of now (2016-12-15), no, as can be found at https://developers.google.com/places/web-service/details#PlaceDetailsResults. There's no other API for that information. You could use the API ratings return to do something alike, but still not the same.
You can track the existing requests for the feature (and star & bump it) at https://issuetracker.google.com/issues/35827350.