No you shouldn't have an issue at all. The only time that you will have enough pressure to explode your bottles is if your primary fermentation is not finished when you bottle your beer. I agree with Bongofury, invest in a bench capper it's well worth the money, especially if your going to get...
Yes as stated above, you will need to add the 9,5L to the mash tun, and when you have finished the mash, drain the mash tun to the boiler and rinse the grains with more water to leave you with 27L in your boil kettle before you start.