luvhuffer brings up a very important point about DirectX 9.0c compatible drivers vs. DirectX 9.0 compliant hardware. Whether or not a DirectX 9.0 game can even play on hardware with DirectX 9.0 drivers will totally depend on the game and if the game requires newer DirectX 9.0 features, or is simply using DirectX 7.0 or 8.0 features developed for DirectX 9.0.
DX9.0 adds new ways to take advantage of pixel and vertex shaders, texturing and texture compression and other new features. Modern/new videocards will have the hardware to support these new features. Older hardware will release DirectX 9.0 drivers, but if the hardware for the new features isn't present- games requiring those new features will not be able to play.
Example- 3d hardware designed several years ago to support all the features of DirectX 7.0 has seen DX8.0 and DX9.0 drivers... but these in no way ADD 3d geometry hardware or pixel/vertex shaders to your 3d hardware. They instead make DX9.0 queries fail if a game asks the DX9.0 driver set what level of Geometry processing or pixel/vertex shaders are present. If the DX9.0 game doesn't use pixel/vertex shaders, or if the developers handle lower-end hardware by simply disabling these extra features is something the programmers decide. Newer games like Battlefield2, for example- if there are no pixel/vertex shaders in hardware, the game will simply exit saying it cannot find a compatible DirectX 9.0 videocard. While at the same time, you might fire up Battle For Middle Earth, and this game will instead disable shaders and advanced effects if the hardware doesn't have it.
Sims2 I believe needs hardware T&L (which is a form of geometry processing). Most on-board, integrated hardware does not have this. DirectX also offers some ways to "emulate" this on certain CPU's (like MMX for Intel or 3DNow! from AMD), but it's a dice roll if your system has the correct CPU or video hardware to provide this. The easiest way to ensure this is to get a videocard with AT LEAST DirectX 8.0 compliance, which includes Hardware T&L and Pixel/Vertex Shaders 1.1 (or 1.4 for ATI). Newer DirectX 9.0 cards have even more geometry/T&L capabilities and extend pixel/vertex shaders to V2.0. Even if a game does not need these dx8.0/9.0 features, all bets are off if you do not at least have the "DirectX 9.0 compatible" drivers installed.
DX9.0 adds new ways to take advantage of pixel and vertex shaders, texturing and texture compression and other new features. Modern/new videocards will have the hardware to support these new features. Older hardware will release DirectX 9.0 drivers, but if the hardware for the new features isn't present- games requiring those new features will not be able to play.
Example- 3d hardware designed several years ago to support all the features of DirectX 7.0 has seen DX8.0 and DX9.0 drivers... but these in no way ADD 3d geometry hardware or pixel/vertex shaders to your 3d hardware. They instead make DX9.0 queries fail if a game asks the DX9.0 driver set what level of Geometry processing or pixel/vertex shaders are present. If the DX9.0 game doesn't use pixel/vertex shaders, or if the developers handle lower-end hardware by simply disabling these extra features is something the programmers decide. Newer games like Battlefield2, for example- if there are no pixel/vertex shaders in hardware, the game will simply exit saying it cannot find a compatible DirectX 9.0 videocard. While at the same time, you might fire up Battle For Middle Earth, and this game will instead disable shaders and advanced effects if the hardware doesn't have it.
Sims2 I believe needs hardware T&L (which is a form of geometry processing). Most on-board, integrated hardware does not have this. DirectX also offers some ways to "emulate" this on certain CPU's (like MMX for Intel or 3DNow! from AMD), but it's a dice roll if your system has the correct CPU or video hardware to provide this. The easiest way to ensure this is to get a videocard with AT LEAST DirectX 8.0 compliance, which includes Hardware T&L and Pixel/Vertex Shaders 1.1 (or 1.4 for ATI). Newer DirectX 9.0 cards have even more geometry/T&L capabilities and extend pixel/vertex shaders to V2.0. Even if a game does not need these dx8.0/9.0 features, all bets are off if you do not at least have the "DirectX 9.0 compatible" drivers installed.