After the gum shield the most important thing is too keep warm. Padding/head guards are not really necessary at that age. Layers are important – it is easy to take layers off and on, depending on how hot/cold he is feeling.
We got headguards / body padding for both lads (now 20 and 18) when they were about 13. Both wore it for a couple of years. Son number 1 wears a head guard, because he is a hooker and he has dreadlocks! Son number 2, a second row, wears now padding.
Don’t worry too much about brands – at that age it is likely to get lost or outgrown before it has seen too much use!
Another tip is too take some warm kit for afterwards and take any damp/muddy clothing off. It will add to the washing pile, but the act of putting on dry clothing makes a difference.