That's great, and yes - having defined a property it's up to your own code to act on it as your instrument requires, and if you want compatibility with astronomical systems the standard properties should be considered.
(At the risk of teaching grandmother to suck eggs) - to make your driver executable would be to include the shebang line:
#!/usr/bin/python3
As the first line of your script, and then give your script executable permissions, and you should be able to pass it straight into indiserver just like any other driver. If you are doing this, then make sure there's no 'listen()' method called in your script, so it's not trying to use a port, but will use stdin/stdout as indiserver expects.
If there's any suggestion you, or anyone else, can make to improve the docs at