NHL 09

It's easier to do this with NHL BE A PRO. I did mine with Daniel Alfredsson, A+ overall for the game.

Stay in good position, kill any penalties (don't get any yourself), and get an assist or goal.

Rather than starting a whole new career, which seems really time consuming, just adjust all rules & game play settings in favor of your particular playing style, and save your Be A Pro career right before your first game. If you don't think you are on track for your A rank after the second period or so, just exit out to the main menu and restart. You won't forfeit the match by doing so, and your stats don't take a hit. Worst case scenario, if you get to the end of the game and don't net an A, just reload your original save.

You can, of course, make this even easier by creating a winger with an overall 99 ranking and placing him in the team of your choice.