Looking for some advice from the KLM folks and experts with AMS.

I'll be booking a one way AMS - CPH flight for mid/late July. Currently eyeing a 9:20am departure. I'd like to take the train to AMS from the central station but from what I can see the direct train doesn't begin running till 6am. Given what sounds like a messy AMS and Summer travel, will being at the airport 3ish hours in advance be sufficient? We'll have no checked luggage, do not have status, and will be flying in econ.