Hey -
Just to clarify, you are receiving this message when you try to convert a project from 4.7 to 4.9? Are you attempting to open the project through the project browser and opening a copy or are you right clicking on the .uproject and choosing the Switch Unreal Engine version option?
Based on the message you posted it appears that an open brace “{” is missing from one of the files in your project (FPSGameMode.cpp).
Cheers