Handling snakes very gently is the key to not getting bitten and having a nice friendly snake. You must keep in mind that snakes don't "enjoy" being handled. It is just something they are not used to. But making every handling session as stress free for the snake (though gentle handling) will ensure that both parties enjoy their time together!
It sounds like your daughter really enjoys snakes. This is great! There are many entry level books out there that with a bit of help from you I'm sure a 9 year-old could handle. Reading books and talking to other keepers it the best way to learn about reptiles.