You have one spade trick, three diamonds and six clubs for a total of 10. You need two more tricks. If you can cross to dummy and drive out the ♥A, you’ll have two more tricks easily, but you must get to dummy twice — once to drive out the ♥A and again to cash your winners. If you cross to the ♣J and play the ♥K, East can win the ace and exit with a club. Even if East exits with a spade, allowing you to finesse, it doesn’t help: you’ll still need one more trick.
You have little choice: After you find out that diamonds are 4–1 at trick two, you must take a club finesse by playing low to dummy’s 9. If it succeeds, you can get to work on hearts while you still have a dummy entry with the ♣J. Desperate times call for drastic measures.