It’s been said that about half of all people have an IQ less than 100. Some psychologists have pointed out that those with IQs less than 90 have a difficult time finding good work in advanced knowledge-driven economies, and manual labor has been either exported to other countries or replaced with robots, leaving part of the labor pool underutilized.
So the shape of the idea that would generate 9%+ GDP growth is a set of technologies and/or political configurations that bring people of all IQs enthusiastically into the labor force. Not just employment opportunity, but situations that would be gleefully embraced, and productive, regardless of IQ. Work that is useful and fulfilling and worth doing for all involved.
This is not the actual idea, of course, only a statement of what might be its shape. If I actually had that idea, I would be talking to venture capitalists at this moment rather than typing this comment.
This would be good only for a temporary gain of three to six years of high growth. After that, we would be at full employment, and although the indirect gains would likely flow for a long time, national growth would likely fall below the 9% figure.
What’s more important, though, is that such an outcome (bringing gleeful and productive employment to many) would make a lot of people happier, regardless of GDP growth.