A balanced intake of polyunsaturated oils including omega-3s as alpha-linolenic acid and omega-6s as linoleic acid is essential for health. While omega-9 oils still may be considered a nutritious component of the diet, they are not considered essential.
For the most part, these are all found in plentiful amounts in our diets so supplementation isn’t generally necessary. The exception is DHA and EPA omega-3s, which are polyunsaturated oils found mainly in fatty fish and fish oil supplements that are associated with a wide variety of health benefits.*