Platform for kick pedal for 8 year old

My son has been drumming on an electric kit the past year and wanted to upgrade to an acoustic. We ended up getting a great deal on a used pearl roadshow 5 piece. Everything is fantastic except how big the bass drum is. He has to have the seat lifted up pretty high where just his toes touch the ground to get the toms in a good position for him. Thus - he cant fully press down on the kick pedal... could I theoretically build a little 1-3" tall box platform for the kick to stand on? It would hit the base drum a bit higher... not sure if that's an issue.