Robin scales to 15 Kilotons. Granted that calc applies to a child, Robin was able to oneshot someone superior to someone superior to said child, and said child was superior to a person who could tank that 15 Kiloton attack...but still that's a decently big AP differance. 3.7 in Kenzaki's favor.
Robin's ressurection took an unknown amount of time. Might've been longer than a week, could be a victory still by SBA
While speed ISN'T equal, Robin's Mach 223 while Kenzaki's Mach 72, that makes Robin about 3x faster.
As for their abilities, Robin has some stat amping, so Kenzaki being able to do it too doesn't seem that useful. They also have VERY similar ranges, and Robin frequently did battle with flying opponents, so while Kenzaki's mobility might be better, Robin's own experience handling flying opponents means 'dealing with that before' doesn't mean as much of an advantage for Kenzaki, Robin has too. Stealing the Levin Sword is possible, but Robin's tomes and other magic are pretty safe from being stolen, they're books.
Robin's definitely smarter, and his Information Analysis and Analytical Prediction allow him to know almost everything an opponent can do, and even predict the 'flow of battle'. Iris is also a decent damage booster to help with his AP disadvantage.
Flipside, Sealing and Timestop seem like the two most dangerous abilities in Kenzaki's aresenal, and flight mobility is still useful despite Robin also having experience. Even if Robin can ressurect, being sealed seems like an incap, and Robin doesn't resist Timestop at all, though I'm not sure how big the radius of effect is, the profile doesn't say.
Being faster and smarter, being able to know everything Kenzaki can do, being able to make analytical predictions, and Kenzaki being unable to outrange him even with flight seems decently in favor for Robin (Sealing might not even be useful if Robin can predict and be faster to dodge), but the Timestop has me hesitant to make any call. If the range is large enough that there's no avoiding it, Robin's outhaxed almost immedietly.
Kinda leaning Robin but I can be easily convinced depending on how big the Time stop radius is.
