No. All he could do was make a small change and then let it all play out for itself, and hope for the best. The Butterfly effect, in more words or less, like stated in The Stranger. Rachel said that the Ellimist has butterflies too. And what did the Ellimist do upon hearing that? He LAUGHED. Which i thought was pretty awkward for him to do, but it confirmed Rachel's theory.
He stacked the deck. That "meddling nitwit" (drode was hilarious) knows he stacked the freakin' deck. And luckily he did. But he let it play out for itself. The good thing about Rachel being in the group but not part of the original plan, is her strength. Both her and Jake were very determined people and I guess we could say they were there to lead the team. Jake leads, Rachel the motivation.
If you notice, all the Animorphs had a special gift or tie to the war. Rachel was the only one lacking in that department. She wasnt a strategist, or an advisor, or tech support. She was the Soldier, plain and simple. And she embraced that position and gave it her all, a total badass.