I was in your position of having limited support and a controlling parent at 18. I was desperate to be independent and, after my A levels, went for a number of interviews with the idea of getting a job, leaving home and being self sufficient. I was applying for administrative jobs and some 18+ training scheme positions with large employers.
Every interviewer looked at my CV, looked at my grades (Oxbridge level) and scratched their head. It seemed that they 'could not compute' that a young person with my grades and background would not be heading off for university. More than one frankly told me that I would be better off going to university.
I suspect that, along with concerns about your age, prospective employers are probably scratching their head about you too.
In the end, I stayed home a bit longer (though that was hard), started a university course while living at home and eventually moved out part way through my degree. It was hard and I did envy the free choice and parental support the vast majority of my friends enjoyed. My father did eventually give me some limited financial support but I struggled financially - lived quite hand-to-mouth and a lot of time spent working.
However, I was so relieved to finally be independent that it stopped me from researching the ways in which I could have received more funding support. In retrospect, I should have been accessing student welfare services, access funds and other sources of support. There are discretionary pots of money available and I would have been as good a candidate as the next person.
I studied, graduated and have never looked back.
My honest advice to you is to apply and go to university as soon as you can. Fees and expenses are on an upward trajectory - £9,000 is not going to be the limit forever. See the latest government green paper on higher education.
Once you have a university place, your best bet is to then find an au-pair type role (accommodation for limited childcare and pocket money) in the local area. They do exist, particularly for people who might have school age children. Most importantly, ask for financial support and advice from the university, the students' union, the NUS, charitable trusts and anyone you can think of. Your family situation should not prevent you from getting the education you deserve.
Best wishes.