[cardanome]

Starting with 2d games is very good advice however if the child is mostly interested in 3d, well not the most helpful advice.

Some people here forget that children are way more tolerant of not understanding things than adults are. They just want to get a quick taste not necessary dedicate their life to the study of game development.

I think something like RPG in a Box https://rpginabox.com/ is nice if the child likes Minecraft-style graphics. Alternatively modding an existing games is something that might be of interest. Also blender is perfect for those that are mainly interested in the 3d graphics aspect, as it allows to focus on certain fields like modeling first and has an amazing game engine that can be solely driven by logic bricks: https://upbge.org/#/

Still, I think even something like Unreal should not be ruled out if the child is dead set on making a "real" game (9 years is a bit pushing it but with help it might work out). For a visually-motivated child that has access to beefy computer, Unreal is the perfect tool to get things done early and fast. Load the starter template and they have a character they can walk around with in the first minute. Grab some free-for-the-month asset packs and they can make decent looking levels in a day or two that they can show friends and be proud of. And if they get to the point of needing logic, the visual scripting language is more than enough to make complete games in it.

Unreal is a monster of complexity but but perfect for just hacking together a quick asset-flip demo one can feel good about. They will learn about the realities of game dev soon enough, let them have some fun.