I found this information (originally from Kristinn Örn Sigurðsson) to solve my problem:
To kill it with -9 you will have to list all running manage.py processes, for instance:
ps aux | grep -i manage
You’ll get an output similar to this if you’ve started on many ports:
14770 8264 0.0 1.9 546948 40904 ? S Sep19 0:00 /usr/local/bin/python manage.py runserver 0.0.0.0:8006
14770 15215 0.0 2.7 536708 56420 ? S Sep13 0:00 /usr/local/bin/python manage.py runserver 0.0.0.0:8001
14770 30144 0.0 2.1 612488 44912 ? S Sep18 0:00 /usr/local/bin/python manage.py runserver 0.0.0.0:8000
14770 30282 0.0 1.9 678024 40104 ? S Sep18 0:00 /usr/local/bin/python manage.py runserver 0.0.0.0:8002
14770 30592 0.0 2.1 678024 45008 ? S Sep18 0:00 /usr/local/bin/python manage.py runserver 0.0.0.0:8003
14770 30743 0.0 2.1 678024 45044 ? S Sep18 0:00 /usr/local/bin/python manage.py runserver 0.0.0.0:8004
Then you’ll have to select the pid (which is the second number on the left) for the right manage.py process (python manage.py runserver… etc) and do:
kill -9 pid
For the above example, if you wanted to free up port 8000, you’d do:
kill -9 30144