I talked to a friend last Tuesday night who lives on Whidbey and fishes the beaches regularly. He said that it has been disappointingly spotty. There are some fish, but not in great numbers. It's still probably worth a try, since the reports I'm getting from elsewhere don't seem to be much better.
I fished a west side beach from my pontoon from the flood through slack and into the ebb last Saturday. I brought two Ling Cod to hand but only saw one Coho caught all day by a local fly fisherman who has fished the beach for 8 years. He took the fish about 15 feet from the beach in the main tide rip. His comment is that there have been very few fish showing this year and those that do show are moving quickly down the sound. I fished some large bait schools in the back eddy and they were under no stress from predators. Hopefully, the reports of big Coho in the Straits mean they are working their way toward Puget Sound.
Good luck, Steve