1. Close digikam
2. Mount the camera via MTP in Nautilus (click on the camera icon in the side bar)
3. Unmout the camera in Nautilus (eject button)
4. Open digikam
5. Select Import -> Cameras -> Sony ILCE-9 (auto-detected) -> pictures are shown
That looks like GNOME and digikam fighting for MTP.
I found a way to reliable get digikam working:
1. Close digikam
2. Mount the camera via MTP in Nautilus (click on the camera icon in the side bar)
3. Unmout the camera in Nautilus (eject button)
4. Open digikam
5. Select Import -> Cameras -> Sony ILCE-9 (auto-detected) -> pictures are shown
That looks like GNOME and digikam fighting for MTP.