Maybe I wasn't so clear on my first post.
It wouldn't really throw the person off. I mean, really. The bomb, even for being a bomb and all, doesn't have that much of knockback. If you were to hit the balloon with it, and the opponent was right next to the balloon, the most it could do is provide an extra 8% to you like Anon said, blow up the balloon, and prevent the opponent from possibly knocking you off the edge again...
In this case, I'm assuming you have lost both of your jumps and have your bomb in tow and your Up-B. Now, for all I know this could be really dumb, but in that situation I would probably Z-drop the bomb, space with Zair, and then either Zair the edge or Up-B to the ledge. Sounds way more reasonable. You could also use the bomb to DI, and recover.
This is like saying by throwing down one of Peach's turnips onto the balloon, you can help yourself recover. I understand these two are not the same character, but it really is saying the same thing, only with a different item. (That does relatively the same amount of knockback as does the bomb) You can do soooo much more things that would be very easy to pull off instead of this.
This is a VERY situational 'technique' to do, and actually would probably put you in a worse position then before, since you are once again on the edge of the stage, only with roughly 8% more damage, and now without a bomb to help you attack/DI/whatever with. The benefits are however that you have your two jumps back, and can Fair/Nair/Bair/Uair/Dair to help you.
2/10 for practical application in a real match
4/10 for a benefits in the situation
3/10 overall
Like I said before, I think it's a cool idea and all, but I would definitely not be trying to do this in a match. There are so many more options. Good try though, and thanks for thinking of original applications.