dumb-init software package provides wrapper script which proxies signals to a child, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install dumb-init
dumb-init is installed in your system.
Make ensure the dumb-init package were installed using the commands given below,
$ sudo dpkg-query -l | grep dumb-init *
You will get with dumb-init package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Utilities |
| Package | dumb-init |
| Version | 1.2.0-1 |
| Description | wrapper script which proxies signals to a child |
| Sub Section | Utils |