Osmocote Blend 18 - 5 - 12 (8 - 9M) has a shelf life of approximately 3 years as long as it's stored in a dry, cool place and away from moisture.
According to the manufacturer's product sheet, Osmocote Blend 18-5-12 (8-9M) generally works well in container grown nursery plants and is commonly used in landscape containers and flower beds, so it would likely work well for your purposes. However, for recommendations and treatment information specific to the Nellie Stevens Holly, you could consider reaching out to a local nursery in your area, or to the Master Gardener at your local county extension office.
Osmocote Blend 18-5-12 is not labeled for use on vegetables.
Please view our Fertilizers for Edible Gardens Products for more options that may be suitable for your application.