As far as I can remember Poser 9/Pro2012 were the first to use the one download and your serial number determined if it was Pro or Standard. Prior to 9/2012 Poser Standard came out first followed by the Pro Version. So you had Poser 8 followed by Poser Pro 2010 which was an extended version of 8.

So if you use Poser Pro 2012 SR3.1 that should get your Poser 9 updated.

Poser 5, 6, 7, 8, Poser Pro 9 (2012), 10 (2014), 11, 12, 13