I am a musician and therefore super picky about the music I listen to. WE make kids cds which I noticed someone else already mentioned, but in the interest of not being totally self-promoting, I will share with you my other very favorites.
Dan Zanes and friends are my absolute favorite kids music. All of his cds are great. Catch that Train might be my favorite. You can listen to stuff on itunes to get an idea of the sound.
They Might be Giants is fun, but not as relaxing. More clever and rocking. They are brilliant and delightful. I love Here Come the ABCs best.
Elizabeth Mitchell makes gorgeous cds for kids. They are quieter and sweeter and maybe more appropriate for a 9 month old than TMBG. SHe also made a cd with Lisa Loeb that is quite lovely, Catch the Moon I think it is called.
My son loved James Taylor's greatest hits. Just remember to mute before Steamroller!
I'm from the Nields. We've made 2 cds for families. All Together SInging in the Kitchen and Rock All Day/ Rock All Night. The second one is a double cd. One of up tempos for dancing to or driving to and one of lullabyes for coaxing the little ones to sleep.
A lot of kids enjoy the Beatles too. Don't settle for music that you don't love. There is no reason to listen to annoying, cloying music. Your child will probably end up loving what you love. Enjoy the search!
K. Nields