What is your price point?
I'd try Maggiano's/Plano, Carrabba's/Plano, Patrizio/Allen.... all have some sort of separate dining area.
Higher end... Del Frisco's/Dallas, III Forks/Dallas, Ruth Chris/Dallas
I know these places make reservations for large parties, especially Maggianos because I reserved an area for the homecoming group last year and there were around 20 in that group.
I just checked your dates and there is no Sr High school homecoming that weekend in Plano, FYI. If there had been it would be tougher to get in.
Good luck and Enjoy!