insserv software package provides boot sequence organizer using LSB init.d script dependency information, 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 insserv
insserv is installed in your system.
Make ensure the insserv package were installed using the commands given below,
$ sudo dpkg-query -l | grep insserv *
You will get with insserv package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Miscellaneous |
| Package | insserv |
| Version | 1.14.0-5.4 |
| Description | boot sequence organizer using LSB init.d script dependency information |
| Sub Section | Miscellaneous |