Some other interesting info on the topic:
"The accusation against Pope Pius IX is not new, and it has never been proved and instead ably refuted. This makes it all the more puzzling to see TIA bring it up again. We have dealt with this calumny before and also with the charge that “Pius IX was a liberal” when he was elected, which is a half-truth needing important qualification. Find the necessary information here:
• The Calumny against Pope Pius IX
More specifically, the charge that Pius IX had been a Freemason was examined in detail and refuted by Fr. Herbert Thurston, S.J., in his book No Popery! Chapters on Anti-Papal Prejudice (1930). We have scanned the relevant chapter and make it available here:
• “The Pope who was a Freemason” by Rev. Herbert Thurston, S.J. (PDF)
As the author shows, the various Masonic accusers cannot even get their story straight, differing just on when and where the young Giovanni Maria Mastai-Ferretti (the future Pius IX) supposedly entered the Lodge! Note that the title of Fr. Thurston’s article, “The Pope who was a Freemason”, is to be understood tongue-in-cheek. Pius IX, of course, was not a Freemason. Why, then, has Pius IX been accused of it? Why are there rumors about it?
A little bit of research goes a long way. It seems that at the origin of this calumny are the Freemasons themselves (shocker!). They appear to have made up this accusation against the Holy Father precisely in revenge for his severe condemnation of Fɾҽҽmαsσɳɾყ in 1865. According to one biography of the good Pope:
In the months that followed this public condemnation of Fɾҽҽmαsσɳɾყ, several Masonic publications in France and Italy, intent on revenge, propagated the story that Pius IX himself, in his youth, had been a Freemason.
Apparently it was the Lodge of Palermo that first put out the accusation… In France, the journal Le Monde Maçonnique immediately went into print with this information [in December 1865]. (Yves Chiron, Pope Pius IX: The Man and the Myth [Kansas City, MO: Angelus Press, 2005], pp. 217-218)"