The 16-year-old has shown enough during this season's National Youth League campaign with the Canberra based side to become the youngest player ever to earn a Hyundai A-League contract with the Yellow and Navy, a deal which will keep him at Bluetongue Stadium until the end of the 2011/12 season.
"Mustafa is such an exciting youngster who has been very impressive for the AIS this season, and we are delighted to have secured his services for the next two seasons, as we look to continue to mould our squad with the right mix of youth and experience," said Mariners Executive Chairman Lyall Gorman.
Amini, a creative central midfielder who is equally at home virtually anywhere on the park, will turn 17 in April, and has been earmarked by AIS and Qantas Young Socceroos head coach Jan Versleijen as one of the local game's brighter prospects, and will complete the season with the AIS before linking up with his new teammates in the off-season.
"We saw him when he played against our boys at Seymour Shaw, it was a draw and we had a very strong team out that day but he was outstanding. He dictated play and made things happen," said Mariners Football Manager Lawrie McKinna.
"Since then we've watched him in a few games, and Jan (Versleijen), Gary Van Egmond and Han Berger, everybody in the national coaching panel highly recommend this boy and think he's something special. He's only 16 but he's an outstanding talent and has a huge future. It's these special ones we need to try to get at an early age.
"He's in a full time environment at the institute, but he's a Sydney boy and his Mum and Dad were very keen to get him up here, it's a very tight knit family.
"For him to be on the Coast for the next two years at least is great for him and it shows, it doesn't matter how old you are, if you're good enough, you're old enough."
Amini joins the ever-growing list of Blacktown City products to link up with the Yellow and Navy, having risen through the Demons' junior ranks before winning a scholarship at the Institute.
"It's a great accomplishment and I'm very happy. It's the biggest highlight of my career so far, and to be noticed at the AIS, especially as one of the younger players is fantastic," said Amini.
"I just want to do well in Pre-Season, hopefully work toward a spot on the bench, and then play A-League for the Mariners before the end of the season. I just hope I can repay the faith Lawrie has shown in me by signing an A-League deal at 16.
"They (Jan Versleijen and Gary Van Egmond) have helped me a lot in the year I've been here, so I have to thank them as well."