Can I ride a race board with soft boots and regular bindings?

Technically yes, but you'll sacrifice a significant portion of the board's performance. Soft boots lack the lateral stiffness needed to drive a race board's edge into hard snow at high angles. You'll get a stiffer, more carvy ride than an all-mountain board, but you won't experience the deep, locked-in carves that make race boards special. If you're not ready for hard boots, consider an alpine carving board with medium-stiff flex instead.