I suppose this differs every time because the terms may be directly connected with the country of destination you choose. So it's better to check from some reliable, official source before doing this.
It is hard to assume that shipping it is not illegal in some countries but the better solution here is to do a research or ask someone from that country you want to go to if it is legal to bring some S9 miners in your luggage. But so far, i've never heard such issues in the airport that someone are bringing some S9 miners. I'm sure airport do have some x-ray scan that can see-through to your luggage but i guess they will just accept it as a hardware and let you through.