I got my 10 year old a set of Peltor Youth muffs and they work great. They allow him to hear me good enough and block a good bit of noise as well.
I have a hard time with ear plugs on him because his ears are very sensitive. I would look to see if you could find some small triple flange ear plugs.
For my plugs I use the following and They are nice soft gel I can wear them all day long and not be bothered by them.