I learned BODMAS: Brackets, Orders, Division, Multiplication, Addition, Subtraction. So that calculation goes thus:

1. (1+2) = 3.
2. 6/2 = 3.
3. 3 x 3 = 9.

Though multiplication and division are of equal precedence, and can be switched around to your heart's content. Using BOMDAS (which doesn't sound as cool), the answer is 1. Silly mathematics.