when u send horus lv 6 to the graveyard to level up to horus lv 8, can the special summon of horus lv 8 be solemned in anyway?

No. You can only Solemn Judgment a special summon if the special summon is a result of the monster's own effect like Gate Guardian, for example. In the case of Horus, by the time Horus LV8 comes out, the chain is already resolving, and there is nothing to chain Solemn to.