What does the last line of the abstract refer to, about "deviations from general relativity"? Is it simply a statement that this (and other) observations of gravity waves are another tool for verifying GR's predictions?
That these waveforms (the first one, in particular) appear to follow the basic GR plan at the time of the merger is actually kind of a bummer. As a physicist who makes precision tests of gravity for a living, I'd really hoped that we'd see something unexpected. Instead, the new thing that we learned is that GR continues to be an accurate model, something that was perhaps unexpected on its own.
GW physicists are hard at work on the future generations of GW detectors... In 50 years, a signal like GW150914 might have an SNR of >1000, so we'll see all kinds of detail that may hold more information than what we've seen so far.
Clifford Will's "The Confrontation between General Relativity and Experiment" is an excellent introduction to the state of the art (this is the stock reference for everyone in the field).
That is how I read it, yes.