There are a number of 9MM's available that break down easy. The ones I own or have owned are.
S&W M&P9 My preference
Springfield XD9 Had one prefer the M&P
Various Glock 9MM's haven't owned any but know they are easy to break down.
I would choose based on intended application and fit to my hand as the top priority with breakdown ease lower in priority. IMHO I'd still choose the M&P
Have your local gun shop show you how the ones you are interested in break down. If they can't be bothered to do so they don't deserve your business.