Hi,
To fix the ball, you can simply use a distance joint, have you tried that? remove any gravity effect and it should be pretty close to sticking to your player.
the other solution is to simply parent the ball to the player and disabe physics on the ball while attached to the player.
To Kick the ball, you need to know the direction and force, and use AddForce2d or SetVelocity2d, that's all you need to have the ball kicked.
Now, to pass it going to be a lot more tricky, typically, I would simply kick on the right direction, then the other player would simply catch the ball using triggers.
Bye,
Jean