Does anyone know if 09 led headlamps can be retrofit on the previous model A3?

I don't think so. I am pretty sure the hood and fenders are the same. The bumper and grill are different but the shape of the opening looks to be very similar as well.

The hood has larger flares, the bumper is completely different, and the center grill (what i affectionately call "beardy") looks the same but aren't interchangeable. you are right about the fenders though.

i had a closer look at the headlights on the 09 when i went in for my 1st oil change a few months back --- they were similar shapes, but not identical. the bumper and hood flares are larger and not in the same position as the old one. the headlights are of a similar but not identical shape.

short of finding a good body shop, or replacing ALL of the front end parts together, it's not looking good.

That sucks because I priced the headlights and they were not that expensive. Replacing the whole front end on the other hand would cost a pretty penny. Thanks.

Well, anythings possible. But, I have an 06 a3 and an 09 a3 and they are not even close. So, i don't think it's worth your time and money.