Debian9 shipped with libssl1.1 and libssl1.0.2 packages.
If you’re getting a loader error like this:
/usr/lib/x86_64-linux-gnu/libssl.so.1.0.0: version `OPENSSL_1.0.0' not found
you can download libssl1.0.0 package from https://packages.debian.org/jessie/amd64/libssl1.0.0/download and install with dpkg . It is ok to keep installed libssl1.1, libssl1.0.2 and libssl1.0.0 package versions on the same system.