Generally these apps will fall in one of two categories. coaching and swing analysis and rangefinder and scoring. Here's a look at just a few in each of these general categories.
Rangefinder and Scoring
A quick search for the word "golf" in the Apple Watch App Store produces three scoring apps followed by three swing analysis apps, and there are literally scores of options available.
Golf GPS (FREE) by GolfLogix, Inc. offers 3-D color course maps, digital scorecards and GPS location on thousands of courses around the world.
Golfshot (FREE) Golf GPS + Scorecard + Handicaps by Shootzoom Software offers info on over 40,000 courses, the ability to view your current game at a glance on your watch and even integrates with iMessage. You can even search and book tee times through the app.
Coaching and Swing Analysis
Clipstro Golf (by SPLYZA, Inc. offers instant swing trace video in combination with iPhone, using motion sensing in Apple Watch. Available in multiple languages, including English Japanese simplified and traditional Chinese and several European languages.
Zepp Golf Swing Analyzer (FREE) by ZEPP TECHNOLOGY offers a Smart Coach Training System, Pro Swing Library and Video Swing Capture with the free version of the app. With additional Zepp sensor technology, utilizing a separate sensor which attaches to your glove offers features like 3D swing analysis and comparison of your son swing with those of pro golfers.
You could spend many hours looking through all of the available golf apps for iWatch, the good news is most of them are free or have free versions which allow you to test drive (pun intended) them first. Some also require the use of iPhone at the same time for video analysis or internet connectivity.