1. The problem asks us to find the exponent in the expression $W^8 \times W = W^{\square}$. 2. Recall the rule of exponents: When multiplying like bases, add the exponents. 3. Here, the bases are the same ($W$), so we add the exponents: $$8 + 1 = 9$$ 4. Therefore, $$W^{8} \times W = W^{9}$$. 5. Hence, the number in the box (the exponent to be determined) is $9$. Final answer: $9$.