I can see why people think it is 9 because the problem would never actually be written like this. It is one and here is why...

Fractions are the same as division for example.

1 ÷ 2 = .5
Or
1/2 = .5

So if you make this problem into a fraction, which is what you should do, then you get :

6
_________
2(2+1)

Because the 2 belongs with (2+1). You cannot separate it because it need to be distributed.

So you get 4+2 when you distribute

6 6
____ = ____ = 1

4+2 6

It's one!