I think the whole idea of endogenous money is vastly overrated and the idea of exogenous money is vastly underrated.
Granted, the term is (intentionally, I think) vague. That's why I say "under-" and "over-rated" rather than "right" and "wrong". We've had some readings on it which I've only semi-attended to, and after a whole class discussing it today I am not very impressed by the whole debate.
If you want to say central banks care about interest rates, I'm fine with that. If you want to say that interest rates impact aggregate demand and that influences the broader definitions of the money supply, I'm fine with that. But monetary policy is still done by buying and selling high powered money (as far as I know - I've never talked to someone at the OMO desk), and it's done that way because while causality could run both ways (think of the old use of the discount window or Bagehot's dictums as an example of interest rates "causing" money creation), that's not how it works. Of course there is some target interest rate in mind (and THAT is only what gets churned out of some target inflation rate) - but you buy and sell stuff at the OMO desk because it causes that target interest rate to come to fruition.