My youngest son has been after me to get a 20 gauge shotgun for several months now. While I have a 18.5 12ga that I use for a brush gun for deer, this would most likely be used for skeet, squirrel, and possibly getting into turkey hunting. I have looked at the Remington 870 and the Benelli Nova.
Any thoughts, recommendations?

Really depends on his size and what he can handle most youth 20 gauges have more recoil than a full size but if you have to get a youth model find a semi auto gas operated. o/u's and pumps have a lot of recoil for young kids to start out on if you do a lot of shooting at one time such as skeet or sporting clays

He got into the skeet shooting through the boy scouts, they were shooting full size remingtons

If it were me I would go ahead and get him a full size 12 gauge with a 24 or 26 inch barrel in a semi auto that way he can use it for anything from ducks to deer if he wants to. The reason I say this is because when I was about 8 my parents bought me a mossberg 500 youth 20 gauge and it kicked so hard to me that I didn't ever want to shoot it which made me feel bad because my parents had bought it and I felt obligated to shoot it even thought it was miserable to shoot. I don't know how much your wanting to spend but a friend that duck hunts with me just bought a Beretta outlander in max-4 that I think was $600-$700 brand new and is very pleased with it.

You need to talk to whoever coaches his skeet shooting and get some recommendations if this is primarily a skeet gun.Go to some skeet ranges and see what is popular. I don't believe you want a short barrel if for the shooting sports. Usually longer 28"-32" are preferred.

Gun fit is the most important factor but with kids that's almost impossible because they grow over night. If he can handle a full size go with a 12 ga and like gas operated preferably. If the LOP is a little long that's ok he will grow into it if it's a lot long it may need adjusting and pitch spacers can be added if it doesn't sit flush on his shoulder to keep from brusing his cheek. Teach him proper form from the start and the rest is a piece of cake. I am an instructor for our 4 h shotgun team and there is nothing more enjoyable than teaching kids how to shoot and watch them light up when they start smoking targets.

I had a Remington Ladies/Youth 870 pump when I was a kid. LOP was short, etc.

If you want to teach a kid to shoot properly the gun needs to fit him.

Recoil should be a secondary consideration. With skeet loads 20ga doesn't kick real bad to begin with.

Actually when you are teaching kids especially small kids recoil is a big consideration behind safety of course because if it hurts when they shoot they dont want to do it again. The best way to combat that is proper form and yes that is hard to do if the gun doesnt fit. LOP is what most think makes a gun fit but that is really the least of them although its the easiest to correct. Drop at heel and comb are the biggest and then cast but as fast as young kids grow its hard to get a shotgun to fit perfect without having a custom stock built every year. And not all skeet loads are equal some are light and others are not. to just shoot a few times is not bad but when you are shooting several boxes it adds up quick you just have to start slow and it doesnt take long for them to get going

Recoil is a big factor, he has J.I.A. and that is why I was going with the 20ga and considering the Binelli since all of the reviews I read talked about how much better it is on recoil

The Weatherby SA-08 would be a good choice in a gas gun.

For skeet or sporting clays, get a gas operated 20ga. on a full size frame. I'd look at an 11-87. After each shooting session, pull the barrel of and wipe the mag down with a cleaning rag and you will never have a lick of trouble. I started shooting skeet and 5-stand on an 11-87 12ga.

If the gun fits, he should be able to mount the shotgun with his eyes closed and not move his cheek weld when he opens his eyes. This is the most important factor IMO. If he's looking at his bead, he's not lookin at the target.

If the Nova 20 gauge is anything like the 12 it will knock his shoulder out of joint.

Go to academy and get a yildiz semi auto. They are right at 400 if that's in your price range. Comes with 5 chokes and they are sharp.

Rem 1100 or 11-87 would be a great choice I don't know about the yildiz semi autos but there o/u's have an aluminum receiver which makes them very light and recoil pretty stiff. you can get light loads that really cut down on recoil as well. There are more options for the 12 ga in light loads than the 20 but there are some for both and they still break targets with no problem. You can also have a recoil system installed ISIS , RAD, GRACOIL, BUMPBUSTER to name a few but they can be pricey but are effective. My son has one on his 12 ga and can shoot all day with no problem.

A mercury compensator is also a very good investment for a clay gun. You never know its there except for reduction in recoil.

If this is the same one that is inported by Mossburg then this is a winner. I purchased it for my wife who is recoil sensitive and she loves it.

Benelli is a recoil operated semiauto. Therefore, it has a heavier recoil than a case operated gun like an 1100 or an 11-87.

If you are looking for a light recoiling quality gun that will last, I would get an 1100 or an 11-87. You can get a youth stock or you can buy a second stock and cut it down.