The researchers never used any discs. The 1000TB figure was for a surface area equivalent to a CD or DVD; they're the same physical size, and these descriptions give the reader an idea of what a 9nm feature size means in practical terms.

What they actually developed was a novel resin and a method for etching 9nm dots in it using a specific optical laser setup. If it were to be commercialized, it'd be a new type of disc, and CD/DVD lasers would not be able to read it.