Hi there Anon,
Its great to hear you're interested in Bath!
Timetables and contact hours differ depending on your course and also the time of the year. For all of our courses, your earliest lecture could start at 8.15 (though these are rare, 9.15 is much more common), and the latest one will finish at 19.05. So depending on your commute time if you're planning to live at home, you shouldn't be getting back too late. I did Psychology here and had around 14-15 contact hours per week (equates to around 7 lectures) but with Computer Science and Maths it may well be more due to the content.
Other choices - its great to see you've got a good range of unis - they are all very good universities overall and sound sensible 🙂
Hoping this helps but please shout if you have any other questions!