python manage.py migrate <app> zero
sqlclear
was removed from 1.9.
Release notes mention that it is due to the introduction of migrations: https://docs.djangoproject.com/en/1.9/releases/1.9/
Unfortunately I could not find a method that works on all apps at once, nor a built-in way to list all installed apps from the admin: How to list all installed apps with manage.py in Django?