Vaadin 14, production build and java version 9 not working

Question

I need some of features of java 9 and I have vaadin 14 app. When I changed java.version in the pom.xml to the java version 9, app. is not running in Tomcat server (production build). Tomcat only show static content of / dir.

Build through spring boot work as expected. No errors while the build or in the tomcat's catalina.out.

I try set 9 into pom.xml like this:

<properties>     
    <java.version>9</java.version>     
    <vaadin.version>14.9.6</vaadin.version>     
    <tomcat.port>80</tomcat.port> 
</properties>

or

<plugin>    
    <groupId>org.apache.maven.plugins</groupId>    
    <artifactId>maven-compiler-plugin</artifactId>    
    <configuration>       
        <source>9</source>       
        <target>9</target>    
    </configuration> 
</plugin>

The same result. With java version 1.8 work normal.

How set Vaadin 14 app to java 9+ ? Thx

PS: local and remote default jvm is openjdk 11.