I started the Be A Pro career, firstly to gain the "Star Power" achievement.
The Star Power achievement in NHL 10 worth 27 pointsGet the first star in a match with your Be A Pro character Then I discovered this achievement, and I thought I could gain them simultanesly - but after trying a couple of times, I read the other solutions to this achievement, and thought I would let it be for the time being,.
After getting the Star Power, I went on to the next game, and didn't do very well i this game - got like B overall I think.. but the achievement popped for some reason, so perhaps it pops after you complete another game after you gained the A rating in a game.