Can't install CUDA Toolkit in Ubuntu

Running Ubuntu 17.10 and latest Nvidia driver 390.84

Downloaded and installed the debian for CUDA toolkit 9.1

After installing without errors when I run
nvcc --version

I see

nvcc: NVIDIA ® Cuda compiler driver
Copyright © 2005-2016 NVIDIA Corporation
Built on Tue_Jan_10_13:22:03_CST_2017
Cuda compilation tools, release 8.0, V8.0.61

Why is version still stuck at 8?

perhaps because you haven’t set your PATH variable properly. review the CUDA linux install guide