Does this mean the creator of the Python language is a Microsoft employee now?

Yes, he is employed by Microsoft now. He did step down from Python as BDFL in 2018.

Further, does this mean that Python in spreadsheets only works in the cloud MS Office?

It’s not technically limited to only Microsoft Cloud, but Azure-powered services, but it’s kind of the same.

Implications from the patent being granted are yet to be seen, but it’s not looking good. It will severely limit external tools if MS decides to enforce the patent.