Guessing a Two-Digit Number

Tasyo is thinking of a two digit number. He tells Basilio the tens digit and Crispin the ones digit, and challenges them to guess the number. Their conversation goes as follows: • Crispin: I know the number is not prime. • Tasyo: Correct, it is divisible by 3. • Basilio: Now I know what the number is. What digit did Tasyo tell Crispin?