You have a great prospect there. I would do passing to proficient and then 1 full season or even more of one on one for forwards. This should increase his JS to nice level, Driving and Handling should be awesome (stop training one on one when there are at the levels you want them to be). JS should also train quite fast with this trainng, and even more importantly Inisde shot. I think Inside shot is underrated and it can be very effective for guards. Get it to average- respectable and you are good to go. Then do some outside shooting (JR and some secondary pops on JS). All of this should make him pretty balanced player at the start of the season in which he is 22. Then you have 2 more seasons to finish him off.
Look at his salary and if you can afford more. If yes then its up to you what to increase (OD for sure and other guard skills if you can afford it). If not then i would train ID to respectable and leave him as he is.