It is, but it's expensive to do. There person must buy Destiny and the first2 expansions before August 31st and then buy TTK before February. The digital legendary and digital collector's edition of TTK does not immediately grant you access to the game or the first 2 expansions. There for it will not register that you have the game until TTK is released.

You say expensive.. Yet people on here complaint about having three accounts.. (9 different characters)