1. **State the problem:** Simplify the expression $-9 + 5 \div (-1)$.\n\n2. **Recall the order of operations:** Division and multiplication are performed before addition and subtraction.\n\n3. **Perform the division first:** Calculate $5 \div (-1) = -5$.\n\n4. **Substitute back into the expression:** $-9 + (-5)$.\n\n5. **Simplify the addition:** Adding a negative number is the same as subtraction, so $-9 + (-5) = -9 - 5 = -14$.\n\n**Final answer:** $-14$