Yes, Librium (chlordiazapoxide) is a benzo and it is safe to take with stims. Safe in the sense that they will not react with each other to cause you strange or dangerous symptoms. You would be sacrificing efficacy of both drugs by mixing them together. Obviously the CNS stimulatory effect of the Adderall will be somewhat compromised by a minor tranquilizer, and vice versa. But it can and has been done.
Clonazepam (klonapin) sometimes has fewer cognitive side effects and might be a better choice to take with Adderall. It doesn't usually "dumb down" individuals who take it, so you could probably use it and still get benefit from the cognitive enhancing effects of Adderall.