A 5th year anniversary only occurs once. Tough to work-around that.
It did seem a bit odd that he interrupted that docudrama, but it's likely he planned that speech before the flick was scheduled to run. Had I been watching anything else besides that, it wouldn't have phased me in the least.
It did cut in right at the point the film was about address Rice's role which struck me as too convenient, but it was simply at the top of the hour and the best time to address the entire nation.
The Democrats will obviously pounce, the dingbats... Kennedy with his usual blather ...
Bush had the right and obligation to explain himself and address the nation on the 5th anniversary of the worst strike against america since Pearl Harbor.