What a load of total shite.
She wasn't asked about 9/11 at all. She was asked "You're in American Idiot [the name of the musical], which is set in the wake of 9/11, what did you know about the story before you got involved in it?"
To which her response is: "I knew nothing about it, actually, which made it that much more fun.
"I actually watched the Broadway version on YouTube, and just fell in love with it.
"And just thought ‘wow this is insane’, and meeting Racky Plews - who’s the director and choreographer - just the way she’s put her own stamp on the show and made is so much more clearer for people to understand..."
They're quite clearly talking about the story of the musical, the mention about 9/11 was just a tiny bit of extra contextual information made in passing.