docker-compose remote interpreter with nginx

I followed these steps, and my Python/Django app is starting up according to the console (no errors):

https://www.jetbrains.com/help/pycharm/using-docker-compose-as-a-remote-interpreter.html

app_1 | September 10, 2020 - 15:14:49
app_1 | Django version 2.2.15, using settings 'project.settings'
app_1 | Starting development server at http://0.0.0.0:9000/
app_1 | Quit the server with CONTROL-C.

However, nothing seems to be listening on the port.

Unable to connect

Firefox can't establish a connection to the server at 0.0.0.0:9000.

Note that the difference between mine and the tutorial is that mine uses nginx, and the tutorial doesn't. In the run configuration I specify the port normally used to go via nginx.

version: '3'
services:

  # Main application
  app:
    restart: always
    build:
      context: ./containers/app/
      args:
        - SSH_PRIVATE_KEY
    env_file:
      - ./config/env/files/app.env
    volumes:
      - ./containers/app/bin/:/app/bin/
      - ./containers/app/src/:/app/code/src/
      - ./containers/app/config/:/app/config/
      - ./containers/app/config/postfix/main.cf:/etc/postfix/main.cf
      - ./.git/:/app/.git/
      - ./logs/app/:/app/logs/
      # the line below mounts the XXXX repository at /lib for development.
      # this should be commented out on any environment except dev
      - ./containers/app/lib/:/app/code/lib/
      - app_data:/app/data/
    depends_on:
      - postgres

  # Main database server
  postgres:
    build: ./containers/postgres/
    restart: unless-stopped
    env_file:
      - ./config/env/files/postgres.env
    volumes:
      - postgres_data:/var/lib/postgresql/data
    ports:
      - 5432:5432

  # Nginx -> app uwsgi
  nginx:
    build:
      context: ./containers/nginx/
      args:
        - SSH_PRIVATE_KEY
    restart: unless-stopped
    env_file:
      - ./config/env/files/nginx.env
    ports:
      - ${PORT}:80
    volumes:
      - ./containers/nginx/bin/:/app/bin/
      - ./containers/nginx/config/:/app/config/
      - ./logs/nginx/nginx/:/var/log/nginx/
      - app_data:/srv/data
    depends_on:
      - app

volumes:
  postgres_data:
  app_data:

Does anyone know if this setup is supported? Or what can I do to make it work?

Note, I can add this to my `app` definition in compose:

ports:
  - "8000:8000"

...and also change the run configuration to use 8000 instead, but I'm just really curious if I can go via nginx.