Is rabies post exposure treatment still possible after 8 months?

No, post-exposure: treatment should be done as soon as possible and within 8 days. If someone were to contract rabies, it would be long before 8 months from time of exposure. There is a vaccine that can be given prior to exposure, so if you are going to be at a job or place where there is a high risk of exposure, you should speak to your doctor about that possibility.