Since the angles Z and Y are the same (45 degrees), sides XZ and XY are the same. So XZ is 9 cm.
Then since you have two of the sides, solve for the third using the Pythagorean theorem a2 + b2 = c2. So 9^2 + 9^2 = c2, which simplifies to 81 + 81, which is 162 = c2. Square root both sides to get c = the square root of 162 (~12.7279 or 9 * square root of 2)
So the sides lengths are XZ = 9 and YZ = square root of 162 (which is also 9 * square root of 2)