I've plotted all september months in the GISS-series and indeed, September 2009 was warm. Actually, it was the second warmest September ever recorded.

One swallow doesn't make a summer, but it's a nice answer to all those silly "earth hasn't warmed for ten years" cherry-picked claims. In fact, the GISS ten year moving-average (green line) is at all times high.
It's getting hot in herre ?