Is the keyword "Repeat" considered a temporary spell on top of the initial spell played? For example, does Ravenbloom student get +2 when I play the Repeat effect of a spell?

No, the keyword Repeat does not create a "temporary spell," nor does it count as playing multiple spells.

According to Rule 820.3.a: "Regardless of the number of times a spell's instructions are executed with this keyword, the spell is only Played once."

Because Ravenbloom Student specifically triggers "When you play a spell," and the act of playing the spell only happens once, the Student only receives its +1 Might bonus one time. This is further confirmed by several Riftbound FAQs (including FAQ #8929 and #743), which explicitly state that Repeat modifies how a spell resolves, but does not create multiple instances of the spell for the purpose of counting or triggering card abilities. Therefore, Ravenbloom Student does not get +2 Might from a spell with Repeat, even if you pay the cost to execute its effects a second time.