A general contractor could very quickly tell if the wall is load bearing. Generally, if the wall runs parallel with ceiling joists or trusses, it is not load bearing. A wall that runs perpendicular to the ceiling joists may be load bearing. It is fairly easy to tell from above the wall if you have access. Permit requirements vary, but since you are not adding living space, this is a remodel. Generally permits are not required.
A registered designer or architect could also determine the construction of the house, identify load-bearing members, and develop a plan. This could give you what you need to proceed DIY or to bid the job to contractors. Remember that there will be a lot of work involved in the floors, walls and ceiling to bring these two rooms together seamlessly.