For a while PSP did had official indie support, there was an Objective-C SDK, a later one in C#, but unfortunely they killed both approaches, because like with PS2Linux, probably people weren't using them for actual new indie games.
The related developer sites aren't even online anylonger.
Objective-C? That seems like an odd choice, did they want to attract iOS developers? (I know someone ported the mobile game Angry Birds to PSP at some point). Do you have more information about this?
The related developer sites aren't even online anylonger.