We Need You! Working as a substitute teacher in Idaho Falls School District 91 helps us ensure the very best learning environment for every student, every day. As a substitute teacher, you can pick the number of days you work, as well as the schools and the grades you teach. D91 has openings for temporary and full-time substitute teachers. And, the district offers some of the most competitive pay around with new, higher rates for substitutes with a degree or teaching certificate.