Disclaimer: I just (like in a few days ago) wrote code to directly address the Floppy Disc Controller and Direct Memory Address subsystems on a computer architecture from 1985 to read/write raw data to disk.
After having made the transfer you should take care to deselect the active drive. However, you should not deselect the drive until the motor has stopped spinning. This is best done by doing a busy wait checking the MOTOR ON flag before deselection.
The "disk access light" is on as long as the drive is selected. It's perfectly safe to eject the disk once it has stopped writing, before the motor has spun down and the code (in this example me) has deselected the drive (turned off the light).