Switch your N9 off, than switch it on. When it's ready go one time through the homescreens if you like and then to the bottom in the "app-screen" (side note: the small lag after first scrolling is still there, but for me not a big problem)... If you like you can open a app like "contacts" - it's opening pretty fast, then try to open the "notes" and it will take a while (over 10 sec.).