MOSI and SCK are fixed on the Uno board (if that is what you have). You can't change them, which is why they aren't in the code. They are hardware SPI pins. Rework so you can use those pins (move whatever you are using pins 11 and 13 for, to somewhere else).
Moving latch to pin 9 should be OK, but be aware that the SPI hardware needs pin 10 to be an output, otherwise it goes into slave mode. I would stick with my pins and move other stuff.