Which 9 V DC Adapter Need for MB102 Breadboard Power Supply
Here is the schematic: 



It needs to be rated for the total output current (current on the 5V line plus current on the 3.3V line) you want plus a few tens of mA for the LEDs and regulators. Other than that, any regulated 9V adapter with the right polarity will work fine. Unregulated ones will also work provided the unloaded output voltage isn't too high.