Yes, it can be used for higher audio rates.
It doesn’t multiply the Word Clock rate up to the audio rate, as the Word Clock signal coming from the Rossini Clock isn’t directly replacing the Bartók’s internal clock to directly control the audio. The Bartók locks its VCXO (the oscillator for its own clock signal) to this incoming Word Clock signal which is then used to directly control the audio.
Therefore, the Word Clock rate doesn’t need to be the same multiple as the audio rate being clocked, just the same base (it needs to be a direct multiple of the audio rate).