Yes. You can both write notes for percussion instruments on a staff and apply preset drum patterns and fills. I don’t compose with percussion myself, and I don’t know how the drums and percussion in StaffPad might compare with other programs.

My still-early impression of StaffPad is that it is best for writing scores in a traditional, classical-like format, and detailed knowledge of standard music notation seems to be necessary. It might not be suitable for people who are more comfortable composing with keyboards, rhythm machines, digital audio workstations, etc.

I learned how to write music 50 years ago on paper. Compared to that, this software is a huge advance. Being able to edit scores easily and hear what I write played back is wonderful.