The problem isn’t recording continuously, but making something useful from the sample data, and in the case of the H9000, having the programming tools to do so. Also you need to have data in the buffer before you can do anything.
Playing the same grain of a sample that is always changing will generally result in a mess, except if you can align the sample buffer with the tempo and beat of the underlying audio.
If this sync is out by even a little bit then again, it’s not going to sound good. And to do it smoothly you will need 2 synced buffers that you can crossfade between, similar to how Eventide acheives pitchshifting.