Reply below, moved here from "Help Lounge" is reply to a request by member Bill Walsh for additional ideas for "Isaiah 6".
Isaiah 6 "Here I am..." is an incredibly visual passage.
Calls out for being acted out.
Take a look at the Lego technique described here for building the altar/Temple/coals/seraphim.
I'm sure the kids won't get the connection to the Temple, altar, coals, etc., so if you have time, I'd show them some animated video about the Temple.
Here's an animated one with the narration of the passage:
The Holy of Holies - Isaiah 6:1-8, Isaiah’s vision of God & Seraphim in King Solomon’s Temple
https://www.youtube.com/watch?v=zHb789riuQU (It's free, you don't need to buy it)
Jelly Telly's 5 minutes "about Isaiah" (answers: what Isaiah was "sent" to do). Link removed - no longer works, might be available on "Minno" a paid streaming service, check if you're already a paid subscriber and post below if you found it.
Don't know if this works for you, but I've always liked the version of this song as done by "Kutless," (I used to play this "Petra" song in youth group a long time ago ) This link features Kutless' version with images to it! https://www.youtube.com/watch?v=JuziDS_4EBI