No. It's not. Or, at the very best, that hypothesis is very highly contested and even the people who subscribe to it can't quite agree which languages it's a creole of. Middle English and... Old Norse? Middle French? Something Celtic?

The evidence often boils down to "English has a lot of borrowings" and "English grammar is less inflected than other Germanic languages".

Fair enough, except that most words used by most people most of the time have straight up Germanic origins or were borrowed after the supposed creolization, and English grammar was heading in the less-inflected direction before the various creole-hypothesis invaders started making their mark on the language.

So... what you're left with doesn't amount to much more than bupkis.