I’m writing for an ensemble with samplers and electronic drums. How would you approach notating a sample pad with 9 pads? Noteheads with numbers 1-9 inside? Thus far I’ve notated them based on the sample type, for example an electric bass drum would be a bass drum note with a different note head, but this time they are just samples with no real life counterparts. Has anyone any experience with this situation?
One person is playing the 9 pads? Are they used to reading a drum stave?
If they are regularly reading something like this, then they might like to suggest what is easiest for them? Or if you are regularly going to do this, but the samples are different and would change then showing them in the same way (each of the 9) might well be best, unrelated to the actual sound coming from the pads, which I think is what you are saying.
Are the pads being triggered at the same time sometimes, or all separately, this might help determine how you show them.
Sorry no suggestions here, just thinking if you can clarify, then someone here might be able to answer you in a way that will help 
A drum kit sounds like it’d be the easiest to read. One pad for each line/space equals nine. And then keep the noteheads normal, unless you have a good reason for something else.
I think I’ll try the note heads with numbers inside, that way I can use them on a normal drum part (where the drummer plays acoustic drums as well as the pad). I just find the editing of the note heads a royal pain. Well, one must suffer for art…
As far as the previous question goes: when playing the pad they will be hitting maximum of two pads at the same time. And they are professional drummers with good sight reading skills.