iqtree software package provides efficient phylogenetic software by maximum likelihood, 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 iqtree
iqtree is installed in your system.
Make ensure the iqtree package were installed using the commands given below,
$ sudo dpkg-query -l | grep iqtree *
You will get with iqtree package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Science |
| Package | iqtree |
| Version | 1.4.4+dfsg-1 |
| Description | efficient phylogenetic software by maximum likelihood |
| Sub Section | Science |