Final answer:
The nursing intervention for a laboring woman at 9 cm dilation who complains of pain is to apply counter-pressure to the lower back, also known as a back rub.
Step-by-step explanation:
The nursing intervention for a laboring woman at 9 cm dilation who complains of pain is to apply counter-pressure to the lower back. This technique, also known as a back rub, can help relieve discomfort and provide comfort during labor. By applying firm pressure to the lower back with the palms of the hands, the pain signals are interrupted and the woman may experience some relief.