Most molded Kydex style holsters are very gun specific and the M&P will not fit the SD9VE. Nylon ones yes. There are so many choices out there. If you have any gun shows in your area that is a good start as you can try on lots of options.
Any idea on where you will carry. Inside the pants, belt, position, all of these come into play.
I feel the most important thing is understanding the proper draw method and placement for quick access that also fits your body shape and needs. Everyone is different.
Here is a description that I have written to help newer gun enthusists to pick a holster design.