Traveling to Miami with 3 friends on Sep. 30-Oct. 4. I will be staying in South Beach. Is it safe? Do they have power back on?
As of 14 SEP 2017, parts of South Beach are still without power.
Your best plan is to stay in contact with your hotel or host. Power should be restored by this weekend and two weeks is enough time for most properties to be fully or near fully operational.
Is it safe, yes. Will you have the best experience possible, probably very close. If there are certain attractions or activities you were looking forward to, you should look them up on line as well. The Zoo will be closed for several weeks while Miami Sequarium and Vizcaya are still assessing damage.
Also, don't count on a trip to the Florida Keys.
Disclaimer: I live there so my perception of the 'damage' is different than what a tourist would see. Would I travel to Los Angeles following an earthquake? Sure. Would I recommend someone else go...maybe not so much.