Prop for a 1987(?) Mariner 15HP

I have a 1987 Mariner 15HP (titled as such at least, I'm not the original owner) and I'm looking for a replacement prop.
Here's the model / serial number: 15M 684C S 037408
The 3 blade prop currently on it (damaged by thieves as they tried to steal the whole outboard) is a 9.25 x 12, and also has 3920R stamped on it. It has 8 teeth / splines.

I've not had any luck finding a replacement online that is the same diameter and pitch. I'm not sure how advisable it would be to go up to a 10" diameter, but it would just clear based on my measurement, although a 10.5" diameter would definitely not work. I only mention the 10" diameter as a possibility because I've seen one listed online that claims to fit a 1987 Mariner 15HP that is 10 x 13 and another that is a 10.5" diameter that is 10.5 x 11.

This outboard is run on an old 14' Sears aluminum featherlight. I'm honestly not sure if the current diameter and pitch is the right fit, but I can tell you that it makes that boat fly. It is almost too fast, IMO, when there's only one person in the boat.

Any help / prop suggestions would be appreciated...

Hello fsn77,

here is link to our Propeller Section I will recommend a 4 blade 11 pitch.

Just to clarify, as while I've had a boat for several years now, I've never had to replace a prop before (lucky, I guess)...

Based on that page in the link, I need to see the Yamaha section because my outboard is from Japan (sorry, I neglected to mention that in my original post). On the Yamaha page (aluminum props), I'm then looking at Model A (9.9-15HP, 8 tooth spline with through hub exhaust), AMITA 4, rubber hub, part number 3113-093-11 as a proper 4 blade 11 pitch (9.25 x 11) prop for my outboard, correct?

Wow... I feel like such a NOOB! Oh wait, I am a noob. LOL

Thank you for your help!

yes is is the correct number from that application

Ok, thank you so much!