I'm not sure, because I'm just startet a test, but if you have an old dynasty saved day 1 in the 09-10 season, it could be possible to play with the new roster in the right season.
What to do?
Step 1: You need an old dynasty with no games played in season 09-10. Which Roster you used in this dynasty isn't important. Make a copy from the dynasty folder
Step 2: You start a new dynasty with the new roster, but the same team. Save it just on day 1.
Copy the appearance, coaches, staff and players folder from this new dynasyty folder into the copy.
Step 3: Start the copy
If everything works:
All players have the right age, because its 2009.
If not, well it was just a copy, wasn't it?
Maybe this could be a way to make a great patch like 0,0001% better