So my car is nearing about 15 years old. Its a 94 bonnevillle ssei with only 70k miles on it. But various plastic parts are breaking in it. Like vents and hinge parts. I was wondering if there was any hardcore superglue or epoxy that I could use to glue them back together or if there was another solution to my problems.

The best solution is replacement. Jimmyfloyd usually has many of these parts and is a good guy. Also post up in the wanted section and someone may have some spares laying around.