This sounds like a really weird idea to be honest.
Firstly, it won't affect PageRank at all, because that is all to do with inbound links (see https://en.wikipedia.org/wiki/PageRank for a primer).
I'm guessing though that you meant whether it would affect how your site ranks for that keyword. It would probably help, but only marginally, and depending on how you do it, it might actually hurt.
If you do go ahead with it, make sure you do the redirect properly. You're going to want to do a 301 redirect, which, since you mentioned Wordpress, you can do using the wp_redirect function, passing 301
as the second parameter. You need to ensure that your original home page can not be accessed at all, because you don't want to have duplicate content.
On a philosophical rather than technical note, it's clearly an attempt to game Google. I generally take the approach that I should code and write for a human audience, and that if I do that well, Google's constantly evolving algorithms will notice and reward me for it. Therefore I personally pay little attention to trying to game it, because Google is likely to figure it out and either ignore it, or worse, penalize it, in the future.
I'd therefore instead write on your home page about how you are a great digital agency. Include digital agency in your name (eg. Sam's Digital Agency), and make sure your name is in <h1>
tags, etc. etc.