I started from scratch and I am pretty sure I didn't had a basically blank (ghost ?) icon of SX Installer inside the installed game list visible in SX Installer
In homebrew list, the correct icon is displayed.
I am already on latest OFW and CFW using Emunand which is also updated to 9.1.0. The blank Icon is SX Installer app (it is not a game or another app). Should I try to uninstall SX Installer via SX Installer ?
You should be able to just click "+" to delete the blank icon or you can try in the Settings/Data Management to delete it. I would download a fresh copy as maybe the NSP is corrupt and could not install properly.