I nine year old would most probably use a 3/4 size acoustic, classical guitar or a full size electric as the necks are still pretty small to get their hands around. Having said that I am 19 and I still like playing the Taylor Baby Spruce guitar as much as my full size Guitars.
Whether or not you use your penis will have no effect on its size.
No it cant.
no
8
no not really
macys and tristans ears
Yes.
5.1 Inches
well it really depends on the size of the 5 year old
Normally 10 year old girls are a size 5, but size 4 is normal too
Not if you are healthy and comfortable with the size
36 A, but it depends on the person