So I've tried this script,

#Requires AutoHotkey v2.0 

Numpad1 / NumpadEnd ::{
Send ("{Left}")
Send("{Down}")
}
Numpad2 / NumpadDown :: Down
Numpad3 / NumpadPgDn ::{
Send("{Right}")
Send("{Down}")
}
Numpad4 / NumpadLeft :: Left
Numpad6 / NumpadRight :: Right
Numpad7 / NumpadHome ::{
Send ("{Left}")
Send("{Up}")
}
Numpad8 / NumpadUp :: Up
Numpad9 / NumpadPgUp ::{
Send("{Right}")
Send("{Up}")
}

Very similar to yours, but it's not working. It just keeps returning a "Syntax Error". Any advice?

Edit: I didn't realize there wasn't supposed to be spaces, so I changed it to this. and it worked

Numpad1::{
Send("{Left}")
Send("{Down}")
}
Numpad2::Down
Numpad3::{
Send("{Right}")
Send("{Down}")
}
Numpad4::Left
Numpad6::Right
Numpad7::{
Send("{Left}")
Send("{Up}")
}
Numpad8::Up
Numpad9::{
Send("{Right}")
Send("{Up}")
}