It could be ACPI issue where they hide the trackpad unless Windows 10 or above is detected. It’s possible to fix that but can’t give assistance for it.
I recommend reading this OpenCore Hackintosh touchpad ACPI patching guide Fixing Trackpads: Manual | Getting Started With ACPI
They mention that some ACPI will check if OS is above a certain Windows version and disable the trackpad if that’s not met. It’s fixed by replacing _OSI (os detect) function with a modified call that always returns true when running on Darwin (macOS). You will need to change that to be Windows 2009 (Windows 7)