The day after Iowa, he phoned Kennedy and pressed for an endorsement, making the case for his wife. But Bill then went on, belittling Obama in a manner that deeply offended Kennedy. Recounting the conversation later to a friend, Teddy fumed that Clinton had said, A few years ago, this guy would have been getting us coffee.If you read it real carefully the supposed Clinton quote isn't in quotes. That means it's not an actual statement from him. If you read it even closer it's a third or fourth person account of something Clinton said on the phone. It's hearsay at best.
Let's suppose, though, for a moment that Clinton actually said it. I don't think he was meaning Obama would be getting them coffee because he was black. It's a reference to Obama's experience. He would be getting them coffee because compared to the Kennedy's and the Clinton's, Obama has entry level political experience. Bill Clinton is not a racist and even if he said the inferred sentence, it's more of a experience slur than a racial one. The only way you can make it a racial statement is on purpose. But the larger point is it's a not a quote the authors of the book directly attribute to Clinton.