It is currently only in 9.6 repository. Any tests are really appreciated, before pushing it to other branches. I added about 30 new packages to repository to satisfy dependncies. Feel free to report the issues pgadmin- hackers@PostgreSQL.org, or to pgsql-pkg-yum@PostgreSQL.org (preferred) lists.
After installing a fresh OS from CentOS-7.0-1406-x86_64-DVD.iso and then doing an yum update, and then installing the repository rpm pgdg-centos96-9.6-1.noarch.rpm, and then running "sudo yum install pgadmin4", it ends up with: