For one thing, average is a matter of opinion. I absolutely adore short, "dorky" looking guys. Guys who have a lot of muscles or are "manly" are kind of a turn off. So the 9/10 girl may think YOU'RE the 9/10 guy because her tastes skew your way.
Secondly, it might be a *little* hypocritical to focus your attention on 9/10 girls but worry about your looks being average... In other words, you expect THEM to look past your looks, but you won't approach an AVERAGE looking girl. What you might wanna try is to stop focusing so much on the numbers, and hit on the whole range... you might find you hit it off way better with a cute 7 girl that a hot 9/10 girl. Just a thought.
YES! most girls LOVE whn they are approached :) I know some girls that you would call a 9 or a 10 and they love nerds more than average guys (a little weird,.) I know I like average guys more because they tend to care more and are way sweeter than the 9s and 10s that are guys (cause they just think they are hot) although there are some "9/10" girls that are just bitches so watch out for those :p do you know: 9/10 girls are actually asked out the least of all people because guys feel too intimidated? so ask away! I bet it will make them happy :) and if the average guy dresses nicely and is in a pretty good shape then its even better :) ! good luck!
Yes, just because she's attractive doesn't mean she won't like you unless she's that shallow, some really attractive girls don't even know there actually that attractive as men are always intimidated by their looks so they don't get approached that much so they then think there unattractive or something.