By 15 I could earn $200/mo after school saying "you want fries with that?" into a microphone and running a cash register for a drive-thru, and that was at $3.35/hr minimum wage. In Florida minimum wage is $15/hr now, so $200/month is less than 2 4 hour after school or one 8 hour weekend shift a week, even after taxes.

The $9K figure, as I read the summary, is total spent by all contributors to the project, and if they manage to develop a full commercial quality port for under $100K they've beat what the industry players would spend on developer time for the same job by a wide margin.