I would refer you to your adverse action notice and report what is showing on there. If its showing a denial reason of "insufficient collateral", or the likes of, I would report 4 as a denial reason.
If your denial reason is showing as "Unable to finance for terms or conditions requested" you would report 9. If there is something in file such as memo that the lender clarifies the reason of denial (i.e. LTV is too high), you can also report 4 as well with the 9 code.