Welcome to the forum.
I always hate to have to ask such ridiculous questions (please don't take offence!), but are you sure it is a 2009 and sure it is a hemi? A september 2008 build date should certainly put it into the 2009 model year...
To be absolutely sure, you can check your VIN number to make sure everything is as it should be. In the 8th position of the VIN, you should have a '2' for the Hemi, if it is a 2008 and a 'T' if it is a 2009. The 10th position will be your model year...of course, by looking at the motor, you should be able to tell the hemi from the 4.7L as well
As far as I know, those are the only things that would result in the personal settings menu not even having an option to display the eco mode in the message centre...
Even if the MDS is not functioning properly, the option should still be there...I think
Perhaps another member can chime in, but I don't know what happens to the options menu if the MDS is turned off by a tuner...is the option to display the eco mode still there? I would think so, but again, anything is possible!
Did you buy it from a dealer, or an independent? If it was a dealer, take it to them and ask about it. If it was an independent, I wouldn't bother, most don't even know what the MDS system is.
Hope everything gets worked out!