bind9-config: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/bind9-config - from package: bind9

You may install the required package with command apt-get install {package}

Error in other languages:
bind9-config: bevel nie gevind nie
bind9-config: comandă negăsită
bind9-config: comando não encontrado
bind9-config: commande introuvable
bind9-config: command not found
bind9-config: käsku ei ole
bind9-config: không tìm thấy lệnh
bind9-config: komanda nerasta
bind9-config: Kommando nicht gefunden.
bind9-config: kommandot finns inte
bind9-config: komut yok
bind9-config: nie znaleziono polecenia
bind9-config: níor aimsíodh an t-ordú
bind9-config: no se encontró la orden
bind9-config: no s'ha trobat l'ordre
bind9-config: opdracht niet gevonden
bind9-config: parancs nem található
bind9-config: perintah tidak ditemukan
bind9-config: príkaz nenájdený
bind9-config: příkaz nenalezen
bind9-config: команда не найдена
bind9-config: командата не е открита
bind9-config: 命令找不到
bind9-config: コマンドが見つかりません