I can't comment at all as a KR since I've never really paid attention to them. But as far as your safety abilities, I'd say you're on the right track with the exception that your agility is WAYYYYYY too low.
Agility governs your acceleration. Having a speed of 40+ and an agility of 12 means your guy can (theoretically) run pretty fast...but he takes forever and a day to actually get up to full speed. In other words, he has no "burst" speed. You need high agility to achieve that. Agility also is the primary stat that determines your "turning radius"; a player with high speed but no agility can be fast when running in a straight line, but if you suddenly need to change direction, your guy can only do that by making these really weird-looking, wide looping turns. Agility (combined with vision, which you have enough of for now), combined with tackling, is what governs your ability to tackle elusive RB's and WR's.
Other than that, your guy is off to a solid start. For the short term, I'd dump all of your daily training into agility. Your next couple of level-ups, put all 5 points into agility. A general rule of thumb I like to use for safeties is to have your agility at approximately 75% of whatever your speed is, give or take. Early on in a player's career, favoring speed a bit more than that is probably okay, but I would work to always keep your agility at least 50% of what your speed is.
Once you get your agility over 20 or so, I would then switch over your daily training to one of your lower stats (but one that is still important for you). Strength, stamina, and jumping are all pretty important for a SS, and any (or all) of those would make good candidates for your training points. Strength helps with tackling power backs and also increases your chance to cause a fumble when making a hit. Jumping is a surprisingly useful stat for a safety; it is a big factor in determining your ability to make pass deflections (and, I presume, jumping for interceptions) and it also plays a big role in making diving tackles. Stamina governs how quickly during the course of a game your player wears down; the lower your stamina, the more you will see your player's performance drop over the course of a game. Pump your level-up SP's into agility (still) as well as vision, which is another stat you want to keep pretty high. I would say once your agility and vision are both near 30, then you can start putting more into speed.
Ignore SA's entirely in the early part of your career. Nearly all of them depend upon you having high enough base stats in order for them to help you to any significant degree. That being said, when looking long-term, I think the SS's "Coverage Abilites" tree is one of the best SA trees in all of GLB, for any position. All five of those SA's are useful to a SS. Change Direction, Super Vision, and Closing Speed are extremely useful skills for a higher level SS and will help you every single play, whether you are defending a pass play or up near the line of scrimmage for run-stuffing. People on the forums have differing opinions on these, but I would say around level 8-10 is the time to start cautiously investing into SA's.
SS's are fun players, but they are hard to build well since they need to be reasonably high in SO many different areas. Eventually, a season or two down the road, if you settle in on a good team that you like and you expect to be with long-term, some of your decisions as to where to focus your points will be determined by what sort of defensive scheme your team plays. But that's not something to worry about until your guy is level 25+.