I know that some schools require your scores to be <2 years old. I had this question a couple years ago and upon calling some schools, was told that as long as they receive my completed application within two years of the test date, I would be ok. Maybe they list 1/1/09 since someone applying late this cycle (say in december 2010) would have needed to take the DAT in January of 09 in order for their scores to be valid?
If you are unsure, just call the schools. They'll tell you what you need to know.