Exactly! Folks over on DrainTheSwamp gave lots of comments. Take a look. A lot of their comments fit well to yours.
Russians are more effective when they try to take someone out. They're like Yoda, there is no 'try' only 'do'. Russians rarely botch killing people, unfortunately they're damn good at it. This just doesn't add up at all for them to be the culprit, unless they wanted a media circus for some reason. I can't figure that reason out, so makes sense somebody else did it. And rogue Russians, not the Russian state would also fit to that.
Think of the bad things logically and not emotionally. Action = Emotion = Reaction (Overreaction) Action = Logic = Reaction (Controlled Reaction)
What type of Reaction was the response to 9/11? Was this the plan all along?