The PHB says:
Cast a spell at a higher level
When a caster casts a spell using a higher slot
level as the spell, the spell takes the next level for that
molding. For example, if Umara launches a magic missile using one of her
2nd level slots, this magic missile is the 2nd level. Indeed, the
the spell grows to fill the slot in which it is placed. (PHB 201)
According to the rules, an upcast spell counts as whatever level is used to cast it. There is no difference between the level of the slot and the casting level of a spell.
So, minute meteor of melf toss to the 9th level is a 9th level spell and can not be used with contingency because contingency requires the spell, as cast, to be level 5 or lower.