If you would like to reinstall system-config-lvm, you will have to add Debian 9 stretch to your apt sources.list and install it from there. Please note that it is unsupported though.
The removal bug report suggests kvpm as an alternative, but that isn't in Debian any more either:
The partitionmanager package seems to be a more modern KDE equivalent of that though. Other options might include gnome-disk-utility or gparted, depending on your needs.