Not sure I'd boo him personally, although maybe if I were at the game I would join in for the sake of it.
Everyone has their own opinion on the way he left but I think he just ran his course here. We were going nowhere and he wanted to join the best team on the planet, hardly the biggest cause for resentment given he's not an Arsenal man. We all knew he was likely to join Barcelona at some point.
He's barely a footnote in Arsenal's history and should be treated with complete indifference.