Apex Rising (Book One of the Titan Series)

In the year 3018, the humans are fighting a losing war against a genocidal clan of xenophobic aliens, hellbent on wiping humanity out. Humanity's many colonized worlds have united under a single banner to aid in the protection of the species; thus, the United Worlds Coalition was formed.
Five painful years later, humanity is still losing the war against the aliens that call themselves the "Creed of Apex." Apex, the god of war in their belief, apparently unified the many races that make up the Creed against a common enemy; the unlucky humanity that passed through a system controlled by the Creed.
A team of scientists has gotten together, and they have formulated a final resort that may be able to aid the war effort;
the Titan Project.
The scientists gathered a group of 200 likely candidates for the project. They all age from 7-10, and all exhibit the traits needed in a Titan. They were all taken from their homes and brought to a military planet on the inner section of human space.