9" and he was measuring it correctly? You don't measure from the side; you measure from the top, from the part where it joins, to the tip.
If it was from the side, you've easily added another inch on top of the correct measurement.
Plus op, I doubt because you have an average penis size is why girls haven't had sex with you, unless its caused you to be self conscience, and not wanted to chase after girls because of it.
Girls can't tell a guys size from clothes alone.
I wouldn't worry. Average is average for a reason, and if most girls didn't like it, a lot of people would be single, and a lot of girls striving for something more.
In terms of size, girth means a lot more than length with a lot of girls/and in different positions.
If you are average or above average in girth, you aren't too bad.
Sometimes a shorter, but thicker penis, I can imagine being more satisfying to a girl than a long but slim one.
Just a heads up.