Miso is a fermented product, so it's going to have a trace of alcohol in it as a result of the fermentation process. lots of foods - including bread - do have a tiny amount of alcohol in them - in the UK it doesn't have to be declared below 0.5%.
it's entirely up to you, but I personally wouldn't be too worried. you could let it stand for a few minutes to help let the alcohol evaporate off if it makes you feel better. I might think twice if I was planning to consume eight pints of it though
