I am not a physicist, the following is only what I have discovered in my own research.
It would probably become an asteroid belt, but could reform into a planet, given enough time.
According to Ender's Game, the Molecular Disruption Device created a field in which electrons could not be shared. After the field died down, the only thing remaining would be a clump of iron molecules.
Since it just tore everything apart into molecules, we basically have an iron gas left over. After thousands to tens of thousands of years later, you'll have asteroids. Assuming the star is still there, they will likely get spread out in an orbit around the star, thus forming a belt.
The following blockquote explains how gas interacts around a star up to the point of becoming a planet.
If a disk [of gas around a star] does not collapse due to its own gravity, small dust grains in the disk will start to grow as they collide into each other, just like how dust bunnies are formed in the corners of a room. When temperature drops below freezing temperature, ices start to form on the surface of dust grains, making them more sticky and easier to grow. Eventually, dust particles grow from micrometer size, smaller than the diameter of a hair to pebbles, boulders, and kilometer-size planetesimals (a few miles). Once reaching a few kilometers in size, planetesimals become heavy enough to attract more dust and other planetesimals around them, and they start to grow very rapidly into planets. If they grow large enough, they can also attract gas and become gas giants.
How long does it take for a planet to be born?