From what I hear, the languages that support later version of DirectX are unstable/buggy. The question to really ask is, what do you need from DX9 that you'd risk troubled coding?
That's true, but it's pure coincidence. DarkBasic is not buggy because it uses DX9, it was just as buggy when it was DX8. There are a number of extremely stable engines using DX9 out there, they just don't happen to have basic programming languages attached to them ( well one or two interface with VB.Net. ) Not yet anyway.