Check if you can find this function in master database on SQL2005.

But this works on SQL 2008:

Declare @hex VARCHAR(50)

Select @hex = '0x' + '009FF000' -- I added missing zero in front of the string

SELECT Convert(Int, 0x09FF000) , CONVERT(Int, substring([sys].[fn_cdc_hexstrtobin](@hex), 1,4)), [sys].[fn_cdc_hexstrtobin](@hex)