meshgrid() returning 81x81 for situation you describe is correct, but what you indicate seems that you want to first reshape your x,y, and z vectors in 9x9 matrices
x1 = reshape(x,9,9);
y1 = reshape(y,9,9);
z1 = reshape(z,9,9);
surf(x1,y1,z1);
Not sure if that makes sense for your data.
