Yes, it can be done.
For SSH, you will need to find the IP address of the Pi from the Mobile Hotspot settings screen on your phone, and enter this into your SSH client app (e.g. JuiceSSH). Obviously you need to make sure the SSH server is enabled on your Pi (this can be done with raspi-config under Raspbian).
You can use the same approach to connect via VNC (e.g. from the RealVNC Viewer app on your phone).
Also, if you're using the RealVNC server on Raspbian, then you could use the cloud connection feature, then you would not need to enter any IP addresses in order to connect. The viewer-server connection is negotiated via a cloud service, but your phone will need internet access via mobile data for this to work. Note that the cloud service is only used to setup the connection - the data should be sent directly once it is established.