You may well be able to program DX9 or DX10 games on that machine, but you would not get any kind of ground breaking performance out of it.
Chances are you'd be able to see the results of what you're doing but I not would expect anything fantastic, I would expect it to be a bit slow with Blender and in DirectX I would expect low frames per second.
If you truly are intending to do Blender work or game programming, I would recommend getting a proper desktop PC, even a halfway modern laptop would be better.
To me mini-PCs are only really likely to shine at being small "sit beside your tv" type web browser devices. It looks like Nvidia ION can handle HD video.
According to the Nvidia page the ION should be able to handle playing games at a usable speed, but I'd be sceptical about using it for game development.
From your comment I take it you are set on getting this machine and simply want to know if the machine is capable of doing the work.
Quite simply, yes, that machine is capable of doing the work you want so long as you do not expect it to be the same kind of smooth performance you would get from a machine with a decent processor and graphics card.
Make sure you have (at minimum) the recommended 2GB of RAM, otherwise I would expect the performance to be nearly unusable.
There is a big difference between a computer being usable for a job, and it being good for that same job.