Ropata:

 

Go to Jaycar and get a 9 volt adaptor capable of 2 amps. 

 

Or one capable of less amps... it's 200mA not 2000!

:D

Edit: OP, the centre pin is positive, the outer, negative, like *most* power supplies. 

https://www.jaycar.co.nz/9vdc-500ma-ultra-slim-switchmode-power-adaptors/p/MP3146

This would do.