Rooney was sometimes used in different positions during particular matches (Europe, aways against big clubs) where Fergie packed the midfield, but in the vast majority of matches through 06-09 he played behind one of Saha, Larrson, Smith, Tevez, or Berbatov. The major exception was the run-in during 2009 when he played out wide a lot.
Before that he tended to play off Ruud, and since Ronaldo left he's had one season as a proper striker and then then several behind Berba, Hernandez, Welbeck, or Van Persie.