"at the disposal of the thrower" after a made basket is entirely up to the judgement of the official. That's why we make the big bucks.
You'll never find a book interpretation of exactly how long that takes, because it can vary greatly... a if it goes through the hoop and is caught by a member of Team B, it's at their disposal within a second or so. If the ball takes a weird bounce or inadvertently caroms off a foot/knee/whatever, it's going to take a few seconds for the ball to be at Team B's disposal.