Why can't I import com.google.firebase.database in my java app after upgrading firebase-admin from 6.12.2 to 9.1.0

Question

My java application creates Google Cloud Functions. It works when the pom.xml is:

<dependency>
  <groupId>com.google.firebase</groupId>
  <artifactId>firebase-admin</artifactId>
  <version>6.12.2</version>
</dependency>

However after upgrading the version in the pom.xml to:

<dependency>
  <groupId>com.google.firebase</groupId>
  <artifactId>firebase-admin</artifactId>
  <version>9.1.0</version>
  <scope>runtime</scope>
</dependency>

These import statements no longer work.

import com.google.firebase.FirebaseApp;
import com.google.firebase.database.*;

How do I use the latest version and import these dependencies?

Here are the dependencies in the pom:

    <dependencyManagement>
      <dependencies>
        <!-- https://mvnrepository.com/artifact/com.google.cloud/libraries-bom -->
        <dependency>
          <groupId>com.google.cloud</groupId>
          <artifactId>libraries-bom</artifactId>
          <version>26.1.4</version>
          <type>pom</type>
        </dependency>

      </dependencies>
    </dependencyManagement>

  <dependencies>

    <dependency>
      <groupId>com.google.cloud.functions</groupId>
      <artifactId>functions-framework-api</artifactId>
      <version>1.0.4</version>
    </dependency>

    <dependency>
      <groupId>com.google.code.gson</groupId>
      <artifactId>gson</artifactId>
      <version>2.10</version>
    </dependency>

    <dependency>
      <groupId>com.google.firebase</groupId>
      <artifactId>firebase-admin</artifactId>
      <version>9.1.0</version>
      <scope>runtime</scope>
    </dependency>

    <dependency>
      <groupId>com.google.cloud</groupId>
      <artifactId>google-cloud-storage</artifactId>
      <version>2.14.0</version>
    </dependency>
</dependencies>

I also tried removing the version number of the dependency hoping the BOM would take over the version numbers, but that didn't work.

What is strange is that I have looked at the code in github ( https://github.com/firebase/firebase-admin-java ) and can see the class exists in the code ( https://github.com/firebase/firebase-admin-java/blob/master/src/main/java/com/google/firebase/database/FirebaseDatabase.java )

If I look at the maven dependency com.google.firebase:firebase-admin:9.1.0 I can also see the class as shown here:

Thanks in advance for the help.

~Randy