He probably could, but it would be far more right and proper for the House committee to release the memo.
If the President goes over their heads and does it, it looks like he's on the defense, and going around Congress. Not a good appearance, politically, as the release will obviously benefit him.
Much better for him to calmly hold his position, and allow the people's representatives do the honorable thing.
There's also timing to be considered. The government shutdown is currently sucking up all the oxygen in the media. It's important that the release happens at a moment in the news cycle where it will create the maximum impact on the public.
Agree with your sentiments.
After this has stewed for a few days Trump could tweet ...
“Would be better for country if House releases FISA memo.
Don’t want to use Exec. authority to do right thing.”