Thermal conductivity is commonly denoted as $k$ or $\lambda$. The units $\frac{BTU}{s\cdot in^2 \cdot \frac{^oF}{in}}$you stating$\mathrm{\frac{BTU}{s\cdot in^2 \cdot \frac{^\circ F}{in}}}$ you state are perfectly OK, although awkward. I would have preferred to -at least- simplifyto—at least—simplify the inches:
$$\frac{BTU}{s\cdot in \cdot ^oF}$$$$\mathrm{\frac{BTU}{s\cdot in \cdot ^\circ\mkern-5mu F}}$$
or, even better, write the expression as:
$$\frac{\frac{BTU}{s}}{ in \cdot ^oF} = \frac{1055\; W}{ in \cdot ^oF}$$$$\mathrm{\frac{\frac{BTU}{s}}{ in \cdot ^\circ\mkern-5muF} = \frac{1055\; W}{ in \cdot ^\circ\mkern-5muF}}$$
The conversion to SI is the following as follows:
$$1\frac{BTU}{s\cdot in^2 \cdot \frac{^oF}{in}} = 74767.7 \frac{W}{m\cdot K}$$$$1\mathrm{\frac{BTU}{s\cdot in^2 \cdot \frac{^\circ F}{in}} = 74767.7 \frac{W}{m\cdot K}}$$
So the value you've got 9.8 x 10⁻⁶$\frac{BTU}{s\cdot in^2 \cdot \frac{^oF}{in}} $of $9.8 \times 10^{-6}\mathrm{\frac{BTU}{s\cdot in^2 \cdot \frac{^\circ F}{in}} }$ is equal to approximately $0.7327\frac{W}{m\cdot K}$$0.7327\mathrm{\frac{W}{m\cdot K}}$.