You appear to be asking for python scripts executed started from MATLAB Online to execute in your local MATLAB Home instead .
In order to do that, on the MATLAB Online side, you would have to replace the py package with a package that intercepted the request and formed a TCP connection back to your MATLAB Home instance to request that the action be taken, and then the MATLAB Home session would have to report the result back to MATLAB Online.
That might perhaps be possible, but it would be a nuisance to set up. You could perhaps take advantage of PyRO or Parallel Python, but it would not be trivial . https://stackoverflow.com/questions/536370/execute-arbitrary-python-code-remotely-can-it-be-done
You cannot just configure the pyenv on MATLAB Online to tell it to execute on a remote system.
