Shotcrete is a method of placing concrete and the properties of properly placed shotcrete are equal to those of cast concrete. We have seldom seen the use of epoxy-coated reinforcing bar in retaining walls with or without waterproofing. (The California Department of Transportation builds many retaining walls with cast concrete and with shotcrete and seldom uses epoxy-coated reinforcing bar or waterproofing.)
It is important that you use a contractor qualified and experienced in this type of work and who uses ACI Certified Nozzlemen and a qualified crew.