You can break this problem down into distinct cases:
Using 9 characters: The answer was computed above.
Using 10 characters: In this case, 1 character can be used twice. To determine the number of possibilities, let’s first pick which character can be doubled. There are 9 options for picking that character. Next, if we consider the two instances of that letter as distinct values then we can just count the number of ways to arrange unique 10 characters which is 10! However, swapping the two characters (which are actually identical) would not give a new passphrase. Since these are counted twice, let’s divide these out to give 10!/2.
Using 11 characters: In this situation we have two unique options:
One character is used three times and the others just once.
Continuing as in the previous case, 11!/3!.
Two characters are used twice and the others just once.