Higher Education (HE) comes in many forms. You can do higher or degree apprenticeships, which will give you a real experience of employment alongside your studies. There is also the option of studying HE at a college, which allows you to get a more hands-on experience of the field you are interested in. You could also apply for jobs you are interested in straight after sixth form; however, the more qualifications and experience you have the more likely you are to be successful in obtaining a job.
Technically you can, but by law the employer needs to provide you with some training until you are 18 years old. If you are keen to work an alternative might be to apply for an apprenticeship where you will get paid a salary and receive qualifications at the same time. Otherwise you could take on a part-time job alongside your studies.
Some universities and colleges will let you defer your entry onto a course. This means you can take a year out before starting; however, be sure to check whether or not you can do this for the course you have applied for. You also need to make sure you meet the conditions of the offer in the year that you applied. You can defer entry on UCAS when you apply by submitting an application for the following year. In some cases, it is possible to defer after submitting your UCAS application and once you have received your exam results. However, you would need to contact the university or college directly.
You might want to take a year out before starting university to travel, earn some money, volunteer or gain work experience. This could be an opportunity for personal development before going to university or just a break from studying.