Competing in the 2008–2009 ISU Junior Grand Prix, Gachinski won silver at the Spanish event and was placed fourth in Great Britain, thus qualifying for the 2008–2009 ISU Junior Grand Prix Final, where he finished 8th again. He made his senior international debut at the 2008 Golden Spin of Zagreb, where he was placed 8th. At the 2009 Russian Championships, Gachinski was placed 10th in the senior level and won the silver medal in the junior level. Although he was originally named to the team to the 2009 World Junior Championships, he withdrew from the event before the event began due to illness.