Two technicians are discussing fuses technician a says that current flows should be 20% less than fuse rating technician b says that an orange blade fuse will have an amperage rating of nine which technician is correct

The technician A is correct. The current should be 20%  or any given percentage lower than the current for which the fuse is created.

The technician B argues that orange blade fuses have a 9 Amp rating. But they usually have a 40A rating