What should I promote with my PR9 site?

I recently acquired a PR 9 site (verified) and intended to use it in my blog network to help increase the rank of a financial money site. But in my first few articles I am noticing this site is ranking fast, and without any backlinking at all. In fact the site had no backlinks to speak of when I bought it.

Why it was a PR 9? No idea. Last I saw from waybackmachine it just redirected to a foreign university. Before that it had some obscure incoherent content.

But the articles I added recently are being ranked, often times on the first page. I am not even using tags on these blog posts!

So now I am thinking that the PR 9 should be a money site itself.

I am starting to wonder if I could rank any keyword if I optimized it better and directed some high quality backlinks to it.

Google obviously gives favor to high PR sites, even those with no backlinks at all like mine. Will it downgrade it someday? Who knows. But I am trying to keep it somewhat consistent to what it was before by at least linking to the university that once owned it (presumably). And also copied the exact text that used to be on the site before that years ago and used it as the first few posts.

I am thinking of having an article written once a month about the university in question, just to make it look to goog that I am still "associated" with it somehow... even though I won't directly state that I am.

Anyhoo, just looking for a few opinions on what to do with it, money wise. Like I said I am leaning toward financial/gold, but want to really look at my options.

The site name has no real meaning that I am aware of btw. My tag line is the same as it was before the redirect to the university site, which was just meaningless and weird.