Even at such a young age, the boys' fitness and skilful ball control are impressive. Yet the harsh reality is that even among these hand-picked youngsters, only a few will play for Chelsea. Some may sign for lower division clubs; for the rest, sharing a training ground with their childhood heroes will be as close as it gets.
The club discourages the boys from getting carried away but as Dave Collyer, Chelsea's youth development officer, concedes, "most have got stars in their eyes".
"The importance of education is made clear to them. The boys have to realise there are no hard and fast guarantees. The more sensible ones, and their parents, understand what is involved, and react accordingly. To be a professional you have to be single-minded,but that is not until they are 14 or 15. If a boy misses training because he has got too much homework, I don't mind."
Mr Collyer, like several other Chelsea coaches, is a former PE teacher in secondary and middle schools, as well as an ex-player at senior non-league level. He is aware that conflicts can arise between schools and clubs both trying to work with the same 12 and 13-year-old players.
Too much sport too young, especially when played competitively, can cause burn-out or injury. "I don't think the professional clubs are consulted enough by the educational establishment. At 13, boys might be playing for their school under-14 or 15 team - I think the demands that are put on them, physically and mentally, are too great."
By 15, however, the choice between school and a professional career is unavoidable. "About 1 per cent stay on to do A-levels and come in to train here. It is possible to do, but it can be quite difficult," Mr Collyer says.
"It is a short career, and the timescale is such that it is difficult to do A-levels and make a full-time commitment to becoming a professional footballer. But that does not mean we do not talk to them and their parents about it. "
Those lucky enough to be taken on for a Youth Training Scheme spend one day a week on day release to study for a GNVQ in sports and leisure. Once the boys become full-time professionals there will be more time for A-levels, if they wish.
Chelsea has a policy of coaching only those boys who it believes have a reasonable chance of making the grade - quality, not quantity, is what counts, according to Mr Collyer. Of 14 boys who completed the two-year YTS scheme this year, only seven have been kept on by the club.
"It is quite difficult to say to boys, 'You are not going to be good enough to be professional'. You can take two years out of their life, and that is unfair."
Unlike most clubs, Chelsea produces a brochure to help parents decide whether their sons should pursue a career in the game. "There is no directive from us - we don't say we want him to do this or that," Mr Collyer says.
Among the parents at the coaching session were Maggie Tanner and Angie Holmes. They are full of praise for the Chelsea programme, but sometimes worry about the possible impact if their sons are rejected by the club.
"I do drum it into him that there are only limited spaces out there and you have got to be lucky," says Mrs Tanner, mother of nine-year-old Craig.
"They can be let go at any moment, so they have got to be always fighting for their place."
Mrs Holmes, whose son Terry is 10, agrees: "He knows the places are limited. I just think they are really lucky to have got this far."