There is plenty of information on the web concerning diving from kayaks including several people here with various experiences with kayaks and diving. There is not a course for everything, some things you just have to figure out.
What exactly are your concerns?
I took a course in basic (not SCUBA related) kayaking way back. Then I practiced. The world of kayaks has changed with the advent of the modern roto-molded PE sit-on-top (SOT) kayaks. I currently own four kayaks from 10 feet to 15 feet in length, two are rigged for diving, two for fishing. I have been kayak diving in both lakes, streams and warm ocean waters (Destin Pensacola, Panama City, WPB to FL and Keys and Texas coastal) beginning back in the late 90s.
Kayak diving is a lot of work but also a lot of fun and quite rewarding. So is fishing from the them. I strip my SCUBA gear down to the absolute minimum for kayak diving. I do not use an octopus, no pony bottles, no complex or redundant gear, no weight integrated BCs. Tie everything down or put it below in a hatch. Put your gear on and take it off in the water, always stay tethered including your SCUBA.
If you can find a local kayak course (community colleges, adult education, local clubs etc. just learning the basics of rolling, paddling, maneuvering and common watermanship skills helps a bunch. Then just apply your SCUBA, stir and dive. Easy.
The best SOT kayak ever made, and many will agree with me, for SCUBA (or fishing or whatever) is the long discontinued OK Scupper Pro TW. "The SCUBA kayak" is the OK Scrambler, a fat little barge but stable and fun. SIS (sit-in-side) kayaks are NOT suitable for SCUBA diving use.
N