Let's first take a look at #8 to see why (C) is incorrect -that is, why (C) Ofelia cannot play in two consecutive games. This actually goes back directly to the constraints - in particularly constraint 4 refers to "the only game that Ofelia plays in." Don't worry about this - it happens to the best of us. I generally find it a good practice to (when I am really going bonkers about 2 answer choices and really can't eliminate either) reread my constraints and make sure I haven't forgotten or misunderstood something.
Now let's think about #9 and why (B) is not correct - that is why (B) cannot be true. This one require that we think not only about the particular elements they ask us about but also about the ramifications for the entire board. This question presupposes that T goes in the fourth game. In addition to this, L is already in the 4th game - which means that the 4th game is already filled up, which in turn puts us into the first frame with SOS in games 1 through 3. For that reason O cannot play in the 3rd game - she must go in the 2nd game and (according to the constraint above) *only* in the 2nd game.
It looks like both of these questions stemmed from a misunderstanding or forgetting of the fact that O plays only one game. It's good that you're consistent
Probably would be a good idea to get used to rechecking your constraints when you are down to two answer choices and can't eliminate either.
Let us know if you have any more questions about this game!