Parece que não esta funcionando os links:

sudo sh get-docker.sh

Executing docker install script, commit: 1d31602

• sh -c apt-get update -qq >/dev/null W: The repository 'https://download.docker.com/linux/raspbian stretch Release' does not have a Release file. E: Falhou ao buscar https://download.docker.com/linux/raspbian/dists/stretch/stable/binary-armhf/Packages Received HTTP code 403 from proxy after CONNECT E: Falhou o download de alguns ficheiros de índice. Foram ignorados ou os antigos foram usados em seu lugar.

Mesmo seguindo o tutorial da documentação do Docker:

sudo apt-get update Ign:1 https://download.docker.com/linux/raspbian stretch InRelease Ign:2 https://download.docker.com/linux/raspbian stretch Release Ign:3 https://download.docker.com/linux/raspbian stretch/stable all Packages Ign:4 https://download.docker.com/linux/raspbian stretch/stable armhf Packages Ign:5 https://download.docker.com/linux/raspbian stretch/stable Translation-en Ign:6 https://download.docker.com/linux/raspbian stretch/stable Translation-pt Ign:7 https://download.docker.com/linux/raspbian stretch/stable Translation-pt_BR Ign:3 https://download.docker.com/linux/raspbian stretch/stable all Packages Ign:4 https://download.docker.com/linux/raspbian stretch/stable armhf Packages Ign:5 https://download.docker.com/linux/raspbian stretch/stable Translation-en Ign:6 https://download.docker.com/linux/raspbian stretch/stable Translation-pt Ign:7 https://download.docker.com/linux/raspbian stretch/stable Translation-pt_BR Ign:3 https://download.docker.com/linux/raspbian stretch/stable all Packages Ign:4 https://download.docker.com/linux/raspbian stretch/stable armhf Packages Ign:5 https://download.docker.com/linux/raspbian stretch/stable Translation-en Ign:6 https://download.docker.com/linux/raspbian stretch/stable Translation-pt Ign:7 https://download.docker.com/linux/raspbian stretch/stable Translation-pt_BR Ign:3 https://download.docker.com/linux/raspbian stretch/stable all Packages Ign:4 https://download.docker.com/linux/raspbian stretch/stable armhf Packages Ign:5 https://download.docker.com/linux/raspbian stretch/stable Translation-en Ign:6 https://download.docker.com/linux/raspbian stretch/stable Translation-pt Ign:7 https://download.docker.com/linux/raspbian stretch/stable Translation-pt_BR Ign:3 https://download.docker.com/linux/raspbian stretch/stable all Packages Ign:4 https://download.docker.com/linux/raspbian stretch/stable armhf Packages Ign:5 https://download.docker.com/linux/raspbian stretch/stable Translation-en Ign:6 https://download.docker.com/linux/raspbian stretch/stable Translation-pt Ign:7 https://download.docker.com/linux/raspbian stretch/stable Translation-pt_BR Ign:3 https://download.docker.com/linux/raspbian stretch/stable all Packages Err:4 https://download.docker.com/linux/raspbian stretch/stable armhf Packages Received HTTP code 403 from proxy after CONNECT Ign:5 https://download.docker.com/linux/raspbian stretch/stable Translation-en Ign:6 https://download.docker.com/linux/raspbian stretch/stable Translation-pt Ign:7 https://download.docker.com/linux/raspbian stretch/stable Translation-pt_BR Atingido:8 http://mirrordirector.raspbian.org/raspbian stretch InRelease Atingido:9 http://archive.raspberrypi.org/debian stretch InRelease Lendo listas de pacotes... Pronto W: The repository 'https://download.docker.com/linux/raspbian stretch Release' does not have a Release file. N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use. N: See apt-secure(8) manpage for repository creation and user configuration details. E: Falhou ao buscar https://download.docker.com/linux/raspbian/dists/stretch/stable/binary-armhf/Packages Received HTTP code 403 from proxy after CONNECT E: Falhou o download de alguns ficheiros de índice. Foram ignorados ou os antigos foram usados em seu lugar.