Thank boughtonp  for your observation and encouragement,
in fact, it is not impossible, it takes a little patience and a little time to fine-tune the script.

For the moment I'm using tomcat8 and tomcat9 on the production servers (all Devuan of course) that I'm following, but sooner or later I'll have to switch to tomcat10 and with a bit of patience I'll follow the path you showed me.

OK @Nilli
Thanks for the answer, i will ask debians to Debian Maintaners

Thanks a lot

Oh yeah !!

that's all files
1.  this is tomcat9.service  that is on tomcat9 debian package
----------
#
# Systemd unit file for Apache Tomcat
#

[Unit]
Description=Apache Tomcat 9 Web Application Server
Documentation=https://tomcat.apache.org/tomcat-9.0-doc/index.html
After=network.target

[Service]

# Configuration
Environment="CATALINA_HOME=/usr/share/tomcat9"
Environment="CATALINA_BASE=/var/lib/tomcat9"
Environment="CATALINA_TMPDIR=/tmp"
Environment="JAVA_OPTS=-Djava.awt.headless=true"

# Lifecycle
Type=simple
ExecStartPre=+/usr/libexec/tomcat9/tomcat-update-policy.sh
ExecStart=/bin/sh /usr/libexec/tomcat9/tomcat-start.sh
SuccessExitStatus=143
Restart=on-abort

# Logging
SyslogIdentifier=tomcat9

# Security
User=tomcat
Group=tomcat
PrivateTmp=yes
AmbientCapabilities=CAP_NET_BIND_SERVICE
NoNewPrivileges=true
CacheDirectory=tomcat9
CacheDirectoryMode=750
ProtectSystem=strict
ReadWritePaths=/etc/tomcat9/Catalina/
ReadWritePaths=/var/lib/tomcat9/webapps/
ReadWritePaths=/var/log/tomcat9/
RequiresMountsFor=/var/log/tomcat9 /var/lib/tomcat9

[Install]
WantedBy=multi-user.target
------------------------------------------------------------- end of tomcat9.service

2.  this is the output of the command
$sysd2v-0.3.sh  tomcat9.service
-------------------------------------------------------------
#!/bin/sh
# Generated by sysd2v v0.3  --  http://www.trek.eu.org/devel/sysd2v
# kFreeBSD do not accept scripts as interpreters, using #!/bin/sh and sourcing.
if [ true != "$INIT_D_SCRIPT_SOURCED" ] ; then
    set "$0" "$@"; INIT_D_SCRIPT_SOURCED=true . /lib/init/init-d-script
fi
### BEGIN INIT INFO
# Provides:       tomcat9
# Required-Start: $remote_fs
# Required-Stop:  $remote_fs
# Should-Start:   $network
# Should-Stop:    $network
# Default-Start:  2 3 4 5
# Default-Stop:   0 1 6
# Description:    Apache Tomcat 9 Web Application Server
### END INIT INFO
set -a
CACHE_DIRECTORY=/var/cache/tomcat9
"CATALINA_HOME=/usr/share/tomcat9"
"CATALINA_BASE=/var/lib/tomcat9"
"CATALINA_TMPDIR=/tmp"
"JAVA_OPTS=-Djava.awt.headless=true"
set +a

DESC=\"tomcat9\"
DAEMON=/bin/sh
DAEMON_ARGS=\"/usr/libexec/tomcat9/tomcat-start.sh\"
PIDFILE=/var/run/tomcat9-sysd2v.pid
START_ARGS=\"--user tomcat --chuid tomcat --background --make-pidfile\"
STOP_ARGS=\"--user tomcat\"

do_start_cmd_override ()
{
  install -d -o tomcat -g tomcat -m 750 /var/cache/tomcat9 || return 2
  /usr/libexec/tomcat9/tomcat-update-policy.sh || return 2
  do_start_cmd || return $?
}

-------------------------------------------- end of output command sysd2v-0.3.sh  tomcat9.service

Thanks to those who can help me
Alsen

Thank you,

I will try the conversion tools  sysd2v in case it works as I can make the script available to all of Devunaners

Alsen