10x14 is the answer. You need at least 2' chair push back and your room is a wonderful size. Not sure of the width of your table, but you can easily use the 10x14. That would give you about 2-1/2' on each end, which is good especially if you have "host" larger chairs and it would give you 2' on each side if you table is 48" wide, more if your table is more narrow. 9x12 is definitely too small.

Thank you so much Flo! That was beyond helpful! I am in love with a 10 x 14 so am so happy to hear! I was so worried about the floating island effect. Thank you!

No it will be wonderful. The biggest challenge will be centering it properly for the table and the table under your chandelier(s)!! Those rugs are heavy! Post a photo please. Love to see your room! Sounds grand and wonderful. Get it installed with pros and save your back!

I can't wait to see the rug you picked out! Yes, please post pics. I'm glad you went with a 10x14. It is the perfect size for your room.

Thank you! Here is a picture of the rug (I'm slightly obsessed with Greek Key- absolutely using sparingly of course;) Do you think this print would be too large in a 10 x 14?

I think with the way the print fades around the edges, it will look great in your room. But like Flo said, if your table and/or chairs have prints on them and depending on the walls, it could look amazing or it could clash.

With neutral walls and plain chairs and furniture I think that rug will look amazing.