The striker joined the newly-promoted side after spending two months struggling to find a team after his departure from Chiefs. Moon was released from Chiefs after spending six months under the mentorship of German coach Ernst Middendorp.
The Pietermaritzburg-born forward failed to command a regular starting berth at Amakhosi and was his contract terminated.
Moon had an unsuccessful trial stint with Újpest FC in the offseason after leaving Chiefs at the end of the 2018/2019 season.
The 22-year-old was linked with a return to Maritzburg United when he returned from a trial stint with Újpest FC, but has signed for the Stellies.
“Amped to welcome Ryan Moon to our Stellenbosch FC family,” read a statement from the club.