fcitx-ui-light software package provides light weight xlibs and xft based UI for Fcitx, 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 fcitx-ui-light
fcitx-ui-light is installed in your system.
Make ensure the fcitx-ui-light package were installed using the commands given below,
$ sudo dpkg-query -l | grep fcitx-ui-light *
You will get with fcitx-ui-light package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Utilities |
| Package | fcitx-ui-light |
| Version | 0.1.3-2 |
| Description | light weight xlibs and xft based UI for Fcitx |
| Sub Section | Utils |