Jazz ~
I wouldn’t get too worried about feeding the adult food over LBP since your pup is now nine months old. The difference in calcium is fairly negligible – 1.2/1.5 vs 1.3/1.6, if you got the regular adult recipe and not the Regional Red which I consider to be too high, as is the fish recipe.
Depending upon where you bought it, you can take it back even if you opened it. My local PetCo would take it back. If you bought it online and haven’t opened it, call and see if they’ll switch for you. Otherwise, just feed it and next time get the LBP.
