I got A 8hp and I’m pushing 13mph with 2 people and 15 by myself. Will putting a different prop on the motor help out any ?

Without knowing the rpm, no way to know.  Small outboards don't usually offer much of a selection for props.  It's common for them to have blades that sorta roll back so they will have more slip if over loaded to keep from straining the motor too much.  

"Sometimes" you can find a SS prop that has more normal looking blades with a slight cup for the major brand name motors that improves speed but again though, without an rpm reading, you would need a good crystal ball.  

You’re probably near about as good as you’re going to get. I have my current 9.9 up to 12 mph solo with some prop changes and weight redistributing, and you’re already 3 mph above that on a smaller motor. I’d say you’re doing pretty good “as-is.” Here’s another thread we discussed similar: