The Popes have been requesting a formal visit to the UK for years - it's not as if 2010 was the Vatican's idea.
Moreover, the official start of the Scottish Reformation is a matter of debate. While Scotland did officially make attending Mass a capital punishment offense in August 1560, the pope is coming in September.
The professor is free to hold his own parade a month ahead of time in order to celebrate the 450th anniversary of the codification of the brutal laws that officially united church and government in Scotland - though why a Free Kirk minister would care that deeply is beyond me.
Whether John Knox is the most important figure in Scottish history is a matter of opinion. Some might prefer Robert the Bruce, but for whom Scotland today might be just a larger version of Cornwall.
For the most important Knox in history, I'd vote for Gen. Henry Knox.