No, you cannot create custom players in FIFA 08 on Wii. This feature was omitted from the Wii version despite existing on other platforms.
| Feature | Wii | PS2 | PS3/Xbox 360 | PC |
|---|---|---|---|---|
| Create Player | ❌ | ✅ | ✅ | ✅ |
| Create Team | ❌ | ✅ | ✅ | ✅ |
| Be a Pro Mode | ❌ | ❌ | ✅ (09+) | ✅ (09+) |
| Online Play | ✅ (NWC) | ✅ | ✅ | ✅ |