If two quantities vary inversely it means when one goes down the other goes up proportionally so that the product of the two remains constant.
We write this as xy = k where k is the constant and xy is the product (multiplication) of the two quantities.
For you question the two quantities are y and x2
Therefore our equation is x2y = k
When x = 3 and y = 9, x2y = 32(9) = 81 = k
So now our equation is x2y= 81
When x = .6, we have .62y = 81
.36y = 81
y = 225