Ran DW with Younger Kids and..

it went really well (for the most part.) I ran for 3 kids ages 9-12 and one other adult. In short, a good time was had by all.

There was only one issue that I feel could be a good discussion. One player (my son specifically) was VERY enthusiastic. This is not a problem exactly, except that he wanted to do EVERYTHING. With no turn structure in DW, I had to struggle to give some of the other players spotlight time. One of the other players is much more quiet/shy and could quickly be overshadowed. My son became frustrated a few times because I had to make him wait so other players could give responses. To be fair, this is still better than having players who are bored/passive.

This lack of structure was the only real issue I had. Everyone had a good time overall. I did have to break them of "looking at a list of moves" instead of just describing what they would like to do. For example: At one point, my son wanted to try to incapacitate an attacker without killing them. He says "well, I can't do that, hack and slash kills them." I had to let him know to just describe what he was doing and how, and that he'd be given the opportunity. Breaking habits from other more "rigid" games! However, by the end of the session they were getting it. At the end, the Paladin had an epic one on one battle with an Orc Chief that was full of all kinds of moves that were not just Hack n Slash.

Anyone else ever struggle with making sure the shy types don't get pushed out by the less reserved?

You can provide some structure to DW by ending your description with something directed at a single player. Minimize things like "you all see x, what are you all doing?" and go for more, "You all see x as a bugbear jumps out of the shadows at Augustine. Augustine, what do you do?"

I agree, target specific players, show them an immediate threat. Once the threat is dealt with, or engaged, threaten the next player in the circle. This sounds strange, but don't let the PCs breathe. Keep giving them threats, opportunities, and something immediate that they must deal with. Otherwise, people can get carried away. Good luck with your game, DW seems like a perfect choice for playing with children.

Haven't played yet, but what could work, is to use moves to change the spotlight. An (over-)active player, will sooner or later give you the oppoturnity to use moves and I think you don't have to use it on him.

"Susan, you see, that the nilbog hit's Fred's head with a rusty mace, he staggers and doesn't see two grinning kobolds approaching from behind. What do you do?"

Much the same issue with my young person group as well. They occasionally do get over ambitious and I need to purposefully pause one of them to focus on another. They understand the 'shared spotlight' but occasionally the action gets intense and a chain of moves starts. There's nothing wrong with hitting the pause button on a player to switch the camera angle for a few moments. Structured as it is, Dungeon World allows you to get back to players very quickly. In my adult group I have the opposite as I have one player generally content to never speak up and is just rather shy at the tabletop and I've made sure to consistently push defy danger rolls at him until he acts.

Pholtus help me, I'm running Dungeon World for my oldest son's birthday party and that involves 8 kids between the ages of 8-10 so we'll see how that runs amidst the chaos.

That is brave. I don't even like to run games with 8 players who are adults. It's just too many players for me.

I ran a game for 4 kids aged 8-10 and had a very similar experience. The shyest youngest one eventually turned into the most active. It was great.

But just like you were seeing, it was overshadowing the other players. I slowed her down a little with dice.

"OK that sounds like you attack with your sword, roll 2d6 and lets see what happens." With anything but a 10+ I can involve the other kids at the table.