CCS has taught me that you can get 9 even if you are a 7. But you will have to compensate by having a big penis and a lot of money and a good head of hair.
Now, if you shave your head or go bald, you go down 1.5 points on the scale so you will now be a 5.5, so having a big penis and money will not be enough to get that 9. You will have to hit the gym in hopes of raising your attractiveness back to a 6.5 (remember the gym adds only one point but only if you were average built, if you had a disgusting body it will probably add 2 points), and that probably won't be enough, so you will need a tan to get that extra 0.5 so you can be back at the 7 mark were you previously were with hair. Remember, since your schlong is pretty big and you have money, that can only compensate 2 points.
Now if you have no money and a small penis, you will not get that 9, unless you can hang on to your hair and work out a lot in the gym, but that will only add you one point getting you to an 8, so you may need to find a really good job to be able to bang that 9.