>why would Osama claim/brag responsibility for 9/11
I take it that you haven't looked over 'The House of Saud' yet? It's at your local library, and it's a fast read too. A lot of the questions you keep asking about the relationship between the Bush family and the bin Laden family are answered very well there along with some answers to questions you might ask but haven't thought of yet. Like 'Why does bin Laden seem to grab all of the headlines when Bushie's war policies seem to hit a snag?'.
No one else around here can do the homework for you. Sometimes you have to crack a book or two and make an effort to increase your own awareness.