I've known Globex go down for a few minutes before, but not quite this length of time!
No matter whether you were long or short, the situation is not clear - at the suggested reopening time of 15:15 ES was around 916, and was 905 before the outage. However, with no definite opening time being given yet, when it does open there will be some massive spikes I assume as squeezes take place.
I hope you're not too badly affected by today's outage (I was flat at the time), and I think you did the best thing possible by hedging your position with a spreadbet (something most US traders could not do, only take out a position on SPY, the S&P tracker fund).
However, it goes as a warning to all of us that these sorts of events can and will happen at some time, so they should be budgeted for in your trading plan. Being prepared for the worst is just all part of the game.
I'm looking at the time & sales for ES - the last trade went through at 905 at 11:41:29 and then the next trade is for a single contract at 915 at 16:22:04. Perhaps ES is just being tested, as there are now only 7 trades which have gone through with the last being at 17:34:17, again for 1 contract.
I'm told by a friend in Chicago that it was a Labor Day anarchist hacker that brought the CME down. There's more than one conspiracy theory floating around; but then America is the home of the conspiracy theory; and we are the home of the cock-up theory.