Well, first of all, this is an opinion.
For Madden 09 Peter Moore (EA Sports President) announced it personally in his blog.
But for NBA 09 only a post by EAcrazylegs was said.
I did some research on the subject and found the following:
NBA 08 was developed by HB Studios (hb-studios.com) for PC and PS2 and became the only studio in the ea sports industry to develop PC or PS2 games.
In the HB Studios Wikipedia article (
http://en.wikipedia.org/wiki/HB_Studios) it says they are currently deveoping 4 titles for EA Canada (NBA 09, NHL 09, and two unknown) while just finishing UEFA EURO 2008 (FIFA's mid season release).
And Peter Moore (EA Sports President) blog (
http://itsinthegame.ea.com) wrote a post on March 14th titled "February 20th" that talks about a visit to EA Canada and says "Our core franchises out of this studio, FIFA, NBA, and NHL, are all looking very good and the teams are crunching as they all get ready for alpha milestones."
I don't know what you think of this, but I think the information about NBA 09 cancelled for PC is not true.