My number had a tens digit that is 8 more than the ones digit. Zero is not one of my digits

The tens digit is 8 more than the ones digit. There isn't any zeros.

The maximum digit is 9 because 10 would be 2 digits, 1 and 0.

So say the tens digits is 9.

9 _

The ones digit is 8 less so 9-8 = 1

9 1

There isn't any zeros which is correct.

The answer is 91.