I doubt a Titleist dealer would keep them in stock, but they could probably order it for you. I can't imagine they would take long to receive it.

Or, you might call Titleist,  quote them the serial number, see if its loss is covered under warranty and arrange for the replacement. I don't know if they would send it directly to you because you would need the special wrench to fit the little holes in the top.

The weight screw is a permanently installed weight in the 909 drivers.  If yours came off, please take your driver to a local pro shop and have them call 1-800-833-3450 x 1 for the Warranty department.  They do not send out the screws as they require a special tool to install, but they will put a rush on your driver for you and get it back to you as soon as possible.