The superficial differences between 8 and 9 can be easily mitigated once you realize that both types stem from the same neuroses revolving around desire. Sure 8s are usually more combative and defensive than 9s, but that doesn't make them inherently opposites. Both have deep issue with anger and getting what they want out of life in the face of obstacles. They just take different approaches to dealing with it. 8s will usually be more overcompensatory when faced with what they see as spinelessness in themselves, projecting a tougher exterior to drive away prospective obstacles that could impede them from getting what they want. Anger is externalized, expressed more easily. 9s can become so accustomed to their desires being thwarted that, when unwell, they'll sort of forget that they even have desires at all. You can certainly have flavors of one in the other, since they're both just different expressions of the same fixation.