I have a Garmin 93 SV Plus and Garmin 94 SV Plus mounted on mine, but I use heavily for fishing (two nine inch screens, one with inshore lake maps, the other with coastal maps). They have recently been replaced with new models, but if you can find leftover stock on the 94 SV Plus (saltwater and coastal maps built in), I would highly recommend it. I found mine at
WestMarine for $699. The newer models are $1149. It will provide everything you are asking for and so much more. It includes the transducer, which the transducer alone by itself is over $400 on Garmim website. We've been in 1000 feet of water and 30 miles offshore, never an issue. It's an awesome unit for the price. They won't last long at this price (surprised they still have inventory). Maps very accurate on shallow inshore depth as well.
I can't recommend this 9" built in mapping touchscreen WiFi unit any stronger. It has helped my girl and I catch killer grouper and we just got it.