that is a very long narrow room. You are going to have to go with a 6x9. I would probably get something cut and binded in a 6 x 12, The other thing that stands out to me is a square table that is 52" wide is going to be too big for that space. You need two feet on each side for the chairs, that would mean as soon as someone pushes the chair out, they are in the next room. I think you should look in to a rectangular table.

Whatever table you use, the rug under it should be 36-42" larger than the table top in every direction, yet still not run into baseboards or furniture at the sides. That will allow for chair scoot and sit space without the chairs "falling off" the rug. Tape it out with painter's tape on the floor to see what it might look like and how it fits your space.

If your dining area is only 8' wide and your table is 52", that only leaves you with 44"--22" on each side--for chairs. That's not nearly enough space. You need to rethink your table before you think about a rug.