YourFriendPaul's Killer Sudoku Pattern Generator can determine specific solutions for Killer Sudoku with from 2 to 7 digits, or print out all of the possibilites at once.
I am not affiliated with KillerSudokuOnline, but it is one way to play the game instead of using pencil and the required eraser.
To get a single solutions instead of printing out the whole sheet, just enter the number of digits that the solution requires, and what they add up to. You can also include must have and must exclude numbers. Do not include any spaces, for example to show only solutions that include the numbers 2 and 3, enter 23 in the Must Have box.
In the example, given as a starting point below, the result is all of the two digit numbers that add up to 17: the two digits 8 and 9.
Solve a single Killer Sudoku problem
Number of digits:
Sum of digits:
Must have numbers:
Must not have numbers:
The Full List
The list shows the possible solutions for each number of digits. The numbers in each solution always increase in value ( there is never an entry like 32 or 21), so start looking for the lowest number first when looking up an answer.