1) Larger cedar planters will be fine, and, if you got these at a yard sale, they might need re-potting in any case. If it really is Golden Goddess, that's a clumping bamboo. If you have a running bamboo, it will get rootbound in the container sooner. At some point (several years) you will have to re-pot the bamboo, and that will be easier if the sides of the container slope outward; if they do not, you might have difficulty getting the bamboo out without damaging the cedar container.

2) The bamboo will not require daily watering if they are in the shade and it doesn't get too hot. But 8 days is too long in your area. It's hard to over-water bamboo in pots with drainage holes, so if you could have a neighbor come and flood each pot maybe every 2-3 days, that would be good. You can tell when bamboo need water by watching the leaves: when they start curling in on themselves, it's time to water. So, since October is a ways off, you have some time to determine what your bamboo watering schedule should be.

thanks for all the tips, very useful! I will put them in the shade while I'm away.