1) What could be implications of this? Will we still have internet access?
Unless the debris hit satellite which give you internet connection and you rely on it, there's no noticeable/direct impact for you.
2) How will it impact Bitcoin?
It won't.
3) What would be best strategy to prepare for a world with impassible space debris surrounding orbit? Which assets will be a safe haven?
See
https://en.wikipedia.org/wiki/Kessler_syndrome#Avoidance_and_reduction.