Ember 1.8.1 on IE9, Promise undefined

DEBUG: -------------------------------
ember.js?body=1:15376 DEBUG: Ember      : 1.8.1
ember.js?body=1:15376 DEBUG: Ember Data : 1.0.0-beta.11
ember.js?body=1:15376 DEBUG: Handlebars : 1.3.0
ember.js?body=1:15376 DEBUG: jQuery     : 1.11.1
ember.js?body=1:15376 DEBUG: -------------------------------

Getting the following error when trying to load the app.

Cannot process route index. "Promise" is undefined

The code that it is trying to call is the following:

new Ember.RSVP.Promise (resolve, reject) =>

This works properly on Chrome,Firefox etc.