Angularjs order by specific id first

How to modify my object to order to show first a specific id my object looks like this

{ 1 : [{ id : 1 , name : 'toto'}],
  9: [{ id : 9 , name : 'toto'}]
  15 : [{ id : 15 , name : 'toto'}]
}

I want to show first 9 how can I do this