If I used flurry of blades to 8 might vilemow. Can my 7might unit kill it?

No — your 7‑Might unit deals 0 combat damage, so the 1 damage from Flurry of Blades isn't enough (Vilemaw needs 8 total).

Vilemaw's ability only stops combat damage from enemy units with less Might than it: at 7 Might versus 8, your unit is "less than," so it deals nothing in the Combat Damage Step. Flurry of Blades is a spell dealing damage, not combat damage, so its 1 damage does stick — but Vilemaw still sits at 7 damage short of lethal (Rule 465.2, FAQ 10741).

The only ways the 7‑Might unit gets through are raising its current Might to 8+ before damage is assigned, or lowering Vilemaw's Might to 7 or less (Rule 710). Otherwise Vilemaw's 8 Might kills your 7‑Might unit.