Especially since these development ability levels are not low, one might even say they are quite high.
You should know, Revilia, who is acclaimed as the city's strongest Magic Guide, has a "magic guide" development ability level merely at E. Ota, the city's strongest, has his highest development ability level also only at E. Yet, Reiger's three development abilities have all reached at least C level, with the first development ability "light armor" even trained up to A level, just one level away from the highest S level.
In such cases, it can be imagined how much these development abilities can boost his stats, let alone Reiger's skill [Endless Sight] which also enhances development abilities.
Thus, after Reiger advanced to Lv.8, as far as his stats are concerned, he is already comparable to those a whole level higher than him.
In other words, it is fair to consider Reiger as a Lv.9.
