itunes 9.0.3. When i download a song from a website or https server it automatically downloads to the download folder. In the past the song that was downloaded to the download folder would automatically populate in the itunes library?
You've changed a Safari preference. In Safari - Preferences - General tab - when you uncheck 'Open "safe" files after downloading', you have changed it from auto importing into iTunes until you play each track.
With that setting checked, a music file will auto open iTunes, import it and begin playing since iTunes is the default player. This also "assumes" you have iTunes setup to manage your library which is another setting that can affect this auto import.