CZ 75 has more options for magazines, holsters, sights, and upgrades. I have a P-01 myself which I love. First thing to decide is whether you want compact or full size. Then you can look at pros and cons of polymer vs. metal.
Polymer series is cheaper and lighter and come with the Omega trigger system. CZ 75B series is metal. The P-01 is a lighter weight Al in the CZ 75B family. And you should also think about decocker vs. saftety. With the polymer series you can switch between decocker and safety. But with the CZ 75B you need to make the choice up front.
I have been looking hard at the P-09 and the biggest draw back for me is the stock sights (unless going to the FDE) and the lack of magazine options. I wish the Polymers where able to use the CZ 75B mags which I believe the obsoleted SP-01 Phantom was able to use (I may be wrong on that).
Also, the stock sights on the CZ 75B line are not so good in my experience. The Meprolights are a great upgrade.
And another thing which is personal preference, but I much prefer the decocker on the P-01 or CZ 75BD compared to the P-09. On the polymer stuff the mechanism / interface is different enough to not feel right to me. I would be all over the P-09 if it had more magazine options and a decocker that was like my P-01.