I don't think we can answer this. It's not clear what you're asking.
9^2 = 81
Do you mean 81/8 or 81/8.10?
Or do you mean 9^2/8 in base 10, then convert it to base 2?
81/8 = 10 1/8
10 in base 2 = 1010
1/8 in base 2 = 0.001
10 1/8 in base 2 = 1010.001