Bee will exert every bit of his buuji energy to explode the crater, in one blast. This will leave him defenseless, allowing Kabuto to take him and hide him from Madara. Gaara's sand and the Rock Kage will protect many from the falling, smaller stones.
The destruction caused by his Bijuu bomb is not even close to being large enough to blast this thing. Your scenario requires a massive bs power up, not to mention B would have to already be charging this meteor lvl attack.
A much more likely scenario would be Oonoki pouring all his chakra into making this thing as light as possible, similar to when he carried the turtle.