who is the creator of WAAPP roblox

The creator of Roblox was David Baszucki , and he co-founded it with Erik Cassel. Roblox’s own company information says the platform was founded in 2004 by those two founders.

If you meant “WAAPP” as a specific Roblox game or group, the name is not clearly identifiable from the information I found, so the safest answer is that the best-known creator/founder connected to Roblox itself is David Baszucki.