Ravenbloom and Spell Repeat?

No, Ravenbloom Student does not trigger twice, nor does it receive +2 Might when you use the Repeat keyword on a spell.

According to the official rulings for Riftbound:

• Only one spell is played: Even when you pay the additional cost for Repeat to execute a spell's effect a second time, it is still considered only one spell being played.
• No extra triggers: Because Ravenbloom Student's ability triggers "When you play a spell," and the act of playing the spell only happens once, the Student only receives its +1 Might bonus once.
• Repeat modifies the spell, not the count: Repeat functions by adding the spell's instructions to the resolution process a second time; it does not create multiple instances of the spell for the purpose of counting how many spells have been played.

As stated in the patch notes (Rule 746.3.a): "Regardless of the number of times a spell's instructions are executed with this keyword, the spell is only Played once."