How long a battery lasts depends on what type you have and how much you use it. Most fresh batteries, strong batteries will last a weekend with no problem
Rechargable 9volts, Yes they do. Go with NiMH 8.4volt or better. You can get them at Walmart, Radio shack or a place that caries alot of batteries. You should be able to see what the voltage rating is, if not don't buy it. There is an online company that makes a 9.6volt but you will have to use the search tool to find the web address on this, The AKA, forum. I think it's Tomshardware.com but don't quote me on that.
"Whom shall I send? And who will go for us? And I said 'Here I am, send me.'" Isaiah 6:8