There are 6 ways of arranging 9,5 and n.
Two have been used so the answer must be one of 59n, n95, 9n5 and 5n9
I will show one wrong and then the correct answer
95n - n59 = 5n9
950 + n - 100n - 59 = 509 + 10n
891 - 99n = 509 + 10n
382 = 109n
n = 382/109 wrong
95n - n59 = n95
950 + n - 100n - 59 = 100n + 95
891 - 99n = 100n + 95
796 = 199n
n = 796/199 = 4
So 954 - 459 = 495
The other digit is 4