YOUTH 20GA. ADVICE??

I am having trouble deciding on a 20 gauge for my 9 year old son.  I plan on getting him a 20 gauge that will use for a couple of years until hes ready for a 12.  Right now He shoots a 0.410  and his 243 well considering the fit he has with his current shotgun insn't the best.  Hes' small framed for his age, but handles the firearm well in other aspects(recoil, gun function, saftey, etc).
 
With that said,  I am really considering getting him the mini-bantam 20gauge by mossberg that prices around $350.   The fit would be perfect, but I,m afraid he will experiance a recoil similare to a 12 gauge being that this shotgun only weighs 5 pounds.  Does any one have one?? or would like to shed some light on this topic.  The easiest way I thought I could get around that is to add some weight to the gun(somehow?) and or add a recoil pad to damper recoil if it were too much.  A better half of me says to invest in a semi auto..$350 for a mossberg pump seems to be a bit much for what your getting IMO.
 
Any advice would be appreciated
 
Thanks
 

Try AA skeet loads.

350$ for a 20 gauge is steep I didn't pay that for my12 gauge Mossberg but i like the 870 to but IMO I'd get a semi auto cut a 20 gauge does thump a bit if its high brass

870 it is.. Its a little less expensive. Hard to believe

I got the mossberg bantam for my son about 3 years ago. It's a good gun. It was a tough choice between the mossberg and the remington 870 youth ( I'm a remington 870 guy). My kid liked the feel of the mossberg over the remington. The mossberg bantam comes with a spacer for the stock so you can get the right fit for your kid. It also comes a coupon to get a full size stock at a dicounted price ( I think $50 off). One thing I was told was the mossberg bantam has a full size receiver, the remington has a youth size receiver.So the mossberg can be up-graded to a full size gun by changing the stock and barrel.

As for moving him up to a 20 guage, just start out with low brass shells and he should be ok.

Ithaca Model 37 UltraFeatherlight... you won't regret it. You should be able to get one for around $300 if you can find one, I wouldn't sell mine for 3 times that amount. The thing is the lightest shotgun I've seen, shoots well, is bottom eject and easily converts to right or left hand. 

I bought the Tristar (autoloader) 20 for my daughter when she was 9.  The recoil is negligible compared to my other 20's.   It has been hunted hard, cleaned very little and never jammed for the past 10 years.  For the money I think I got the best deal possible.  My 9 year old son was shooting turkey with it when he was 7.  I expect my son  who is 4 to be hunting with it years from now.  I would recommend an autoloader for any youth simply due to reduced recoil.
 
By the way.  Low brass 7 shot annihalates turkeys at 20 yards.  My kids have 6 beards on the wall to prove it.

Thanks everyone for your input.  You guys have been helpful with different points of view to consider when choosing this shotgun. Opinions are generous, but there somethings to reason from those opinions that are beneficial.
 
I thought it was a long shot.  But I ask L.P Bresney(columnist for wildfowl magazine) by e-mail about what his thoughts were.  He is what I considered to be a shotgun wizzard.   I have read many articles in wildfowl magazine and I thought his style of writing and critique are spot on. 
 
After I ordered the 870 jr. compact for my son.   He(L.P) responded a couple days ago with his response with some similare advice that have been given on this thread.  
 
Thanks again