I'm surprised your G4 did not come with OSX unless it was one of the very first models. Which model G4 is it may I ask? What is the processor speed? Knowing the model/year will help to know how far you can upgrade as far as OSX goes.

Also, how much RAM does your system have? You can check this on OS 9 but for the life of me cannot remember how off hand. lol I think you will find a system tools utility under the apple menu far left of the menu bar top of screen.

Yes, unfortunately the OS 9 browsers are out of date and struggle to load the newer java and html coded web pages, and especially if the page has flash imbedded.

My G4's have been out of action for past 8 months due to moving to a place too small for us (so many things never unpacked.) But we'll be moving soon with luck. So it's hard to give direct advice about OS 9 except from memory.

Torrents on OS 9 ... I'm not sure. My first suggestion would have been an early version of Azureus (now called Vuse), but I am not even sure if it ever ran on OS 9. I used Azureus on one of my G4's but that was with OSX.

OSX system is not expensive to buy btw. I bought Snow Leopard (OSX 10.6) on same day I arrived back from an overseas trip. It cost me $50 AUD. Which is about the same USA currency. I believe the newest OSX is even cheaper but you would not want that version for your computer, I don't think 10.7 would be compatible with a G4. 10.7 is intended for intel macs and lacks the support for older macs.

You might be able to buy a 2nd hand copy of an OSX system disk from someone.

Does your G4 have a CD or DVD burner? Not a player, a disk burner.