Add random number in macro

[KvaGram]

I'm trying this on a new mouse I just got. It had "reprogrammable buttons", but so far I am not that impressed with the features.
So I'm augmenting that with your software.
Anyway, here's my usecase.

I'm playing minecraft, and are building roads and buildings. I have filled my hotbar with a block pallet. I wish to place a random block from the pallet. To do this, I wish to scroll a random number of time (alternatively hit any of buttons 1-9 at random), then hit right-click.

Is this already possible? If not, could you please add it?

Current workaround:
Set one button to continues scroll using wheel(down, 30) macro, then right-click when I need to place a block.