Which creates a weird plot hole if the scene took place in the past. Malifecient created the Soul Eater for Riku then it turned into the keyblade during KH2. How can the Way to the dawn exist before it existed?
Possibly...
The Way to the Dawn already existed and with the Soul Eater replaced it from whatever world the keybalde was currently residing within and the Soul Eater didn't really morph into a Keyblade. Doubtful as it was said it changed into a Keybalde implying that Riku's Blade is new or a new keychain.
The scene happens in the future.
Time traveling allows Riku to leave his keyblade in the past to help the Knights? humm... yeah...
