Your message is a little unclear on what you're trying to do: you use the term tabs, which usually refers to things like browser tabs, but then describe the Alt+Tab shortcut, which switches between windows, not tabs.
In the case that you are talking about browser tabs, most browsers support using Ctrl+<number> to switch between tabs, with Ctrl+9 jumping you to the last tab, regardless of if it's the 9th or not. These must be browser tabs, not browser windows.
Switching between windows can be achieved with Win+<number>, with the order being determined by the order the windows are shown on the task bar. I personally find this particularly useful because I can pin programs to the taskbar and access them by shortcut (EG I hit Win+1 for Firefox and Win+2 for Thunderbird).