It is canon that Kermit the Frog caused 9/11 in the Muppet universe
In the 2002 TV film "It's a Very Merry Muppet Christmas Movie", there's a part where an angel shows Kermit an alrernate reality where he was never born. For whatever reason, the editors didn't really think about it, and continued to use footage with the twin towers still standing for this scene; however, they aren't there in his original universe. Therefore, something that Kermit did in his life, did in fact cause 9/11 in Muppet lore.

In the song "Fireflies" by Owl City he states "I get a thousand hugs from 10,000 lightning bugs." Are we to assume each bug hugs him a thousand times? Or is he only getting hugged by 1/10th of the bugs? Or is each bug is giving him 1/10th of a hug?