The N9 has the same CPU/GPU combo as the Samsung I9003 (Galaxy SL), so any app that runs there should run on the N9, would there be a way to make Google market see a Galaxy SL and show apps accordingly?

Only major differences seem to be:

• N9 has 54 more rows on display
• N9 lacks micro-SD card slot (which could be emulated)
• N9 has far more RAM

None of them should could cause major compatibility issues.