Initially I too thought like you that LG C9 upscaling is not good, just comparing it with other brands in showroom. I too tried playing 1080p content stored in pen drive but was not satisfied. I was really confused because almost all the reviewers clearly mentioned that LG C9 is the best TV and there is no major difference between other brand's premium TVs, particularly upscaling is at par with other brands.
Reading this forum and asking some questions (Thanks to
@Marakk) I understood that it is all about tweaking. Finally, I preferred LG C9. After getting familiar with WebOS applyed FlatpanelsHD setting with minor changes, I am completely satisfied. Here the real culprit is the default settings of C9. Now, I accept it is the best TV and value for money too as it is cheaper than other top brand' premium TVs.