Good observation - guess what? You're right! The 9 typed here appears to be from Lucida Grande rather than Myriad Pro Semibold. Which is, of course, a problem for the credibility of these screenshots.In the screenshot, the 9 in iTunes 9 doesn't look like Myriad Pro to me.
It should also be worth noting that the version string doesn't look right - seems to be missing the proper OS X aliasing, and isn't the version string presented in Lucida Grande Bold?