JET ProgramコミュのALT Pay etc

The general answer to your question is that each situation is different ("ESID"), but I think my situation was pretty typical:

"was just wondering if the pay was enough to live on after rent, bills, travel expenses and food?"
Yes, it was certainly enough for all of that. I ate out a lot and dropped a bunch of cash at bars, pubs, clubs, etc, and even purchased a couple of (cheap, used) cars along the way, and was still able to save a couple hundred bucks a month or so, on average. No problems there. Other JETs who lived more frugally managed to sock away well over $10,000 a year.

"I also wanted to enquire about accommodation - i understand it is provided, does that include any contents such as bed/konro etc? Is it shared accommodation?"
I've never heard of shared accommodation, everyone I knew had his or her own place. Often people inherit/buy bedding and the like from their predecessors, who usually occupy the same unit. At worst, you'll have to spend your first few days shopping for some essentials. No big deal.

"what hours does everyone normally work? 8-4.30?"
I was able to leave closer to 3:30 or 4:00, as I recall, though I knew some JETs in the area who stayed closer to 5:00 or so. ESID.

JET used to make big bucks back in the 90s, but with more and more English teachers in Japan, the pay has certainly gone down. Still, you should be able to live comfortably with the salary, that is if you don't party every night.

In most cases, your city will be responsible to look for an apartment for you. Some will be furnished, some will not.

When I worked as a JET, my working hour was 7:30 to 4.

I'd say that for almost all cases, yes it is plenty to live by. For me, I have plenty of money after bills for shopping, travel to cool places, and putting away money/paying college loans. And I'm absolutely terrible at managing money (I sorta still live paycheck to paycheck), so people with money management skills would probably be able to really maximize their paycheck. Also, I get paid a lot to do very little. In any job back home I'd be working pretty strictly for this kind of money, and here I've got it good, so I'm happy!

For accommodations, I have it pretty good where I live. I didn't have to pay key money since myBOE basically uses my apartment every time a new JET comes in, and my landlady is chill so I didn't even pay the first three months rent until I was all settled in and had everything I needed. My apartment was also furnished and I didn't buy anything from my pred. I have since replaced the futon couch with a new one, and gotten a few other essentials, but overall I had it very good coming. Other JETs have to pay key money, or have to furnish their apartments. It all really depends on your BOE and placement. I've never heard of a shared accommodation, but in my area all the JETs live in the same apartment building, which is fun!

My hours are a little different from the rest of those in my prefecture. I get to school by 8:10 am (usually it is 8:15 or 8:30) and leave at 4:35 (it is usually closer to 4:00 or 4:15), but I get a half day on Friday. And my particular school doesn't give me lunch on Fridays, so I'm outta there by 12:15 (the other JETs in my city eat lunch, so they usually leave after that or after recess). I don't have a ton of classes, so I can often take a morning or afternoon off to run errands if necessary. And the few times it has snowed, my school basically said "you don't have classes and it is dangerous for you to bike in the snow. So don't bother showing up." Woo!

During speech contest times though, I often left closer to 5:30 or 6. Looking back, I think my willingness to work around the kid's schedules and stay late/come early really has made it easier for me to leave earlier or ask time off now. Sometimes I also stay until 5 or later just to stay. When I do this, more teachers usually give me a "sayonara" or "otsukaresama" as I leave than when I leave earlier, so I think they appreciate seeing me staying even if there isn't always a point. Just fyi!