I'm not quite sure what you're describing. Did you replace Kato's connectors with bolts, or did you just bolt their "accessory adapter" onto the pack to keep it from falling off? Either is a cool idea, depending on your goal.
I think by "female 9v terminals" you mean the type of physical connector rather than the voltage. But even Kato's voltage numbers are only approximate. While they're rated as providing 12 volts DC by Kato, my Kato pack puts out 13.4V with no load on those terminals using the standard Kato USA 15V AC wall wart, so you need to be careful what you use them for. It's also unclear what the power rating of Kato's accessory output is. It's likely several hundred mA since Kato sells a signal power supply that's rated for 150 mA and you can connect more than one (although Kato warns that "you may need another power pack" to do more), and the input power to the pack is going to limit it to a total (train plus accessories) of around 1500 mA.
But there's some risk of overheating and damaging something with too high a continuous load. Kato's accessories are mostly short-draw (the solenoids on the switches draw now power except when being thrown), so it may not be designed for the heat produced by continuous high-current accessory use that some kinds of accessories need.
For sensitive electronics, including LEDs, I prefer to use a regulated 12V supply, and at low amperages these are cheap. They look just like an unregulated wall-wart, but include a simple voltage regulator IC inside. Check out
this one for $5.95. It's limited to 600mA, but that's several DCC accessories or 30-90 full-size LEDs depending on how you wire them. And it's probably more suited to continuous running at those kinds of amperages than Kato's accessory circuitry would be.
The bolts are a nice idea though. And if you only need a small amount of power and can accept the inexact voltage, the Kato pack makes a good "accessory supply".
