I have 2 little kids in daycare (aged 1 and 3) and it works, but just barely. My husband works long hours in a different industry and we stagger hours so that the kids aren't spending long days in care -- I drop off around 9 before heading into the office and he picks up around 4:30. I would suggest taking your kid's personality into account when deciding between a daycare and a nanny -- my baby would likely be fine with longer days, but my elder child would find it difficult. My elder would probably be happiest with a nanny, but also probably benefits the most from the daycare setting (socialization, having to deal with multiple teachers, structure). Like all things kid-related, it totally depends on the kid.
The real problem with daycare is that the kid can't go there if they're ill. And little kids in a daycare setting get sick all the time. Seriously, all the time. I've received 3 calls to pick up my sick child from daycare in the month of February alone, and the kid has been too sick to return for several days each time. I'm a litigator, and appear in court at least a few days each week -- it's kind of a disaster. I am in a very family-friendly office, on an 80% schedule, and have family support and it's still a disaster. My spouse is generally unable to respond to the daycare call to pick up the kids, so it tends to fall to me or the grandparents, who pitch in more than is reasonable to expect.
If you have escalated your concerns to the manager and they were dismissed then that says something about the environment where you work.
I do not know how helpful this is but I will throw some considerations out:
Does the Credit "A" receives have an impact on your growth at the firm? Does A's behaviour have an impact on your ability to get a bonus? on your billable target? If it does and you have shared your concerns and nothing is being done about them then I believe you will slowly start to resent your workplace which will naturally lead to you look for another job.
Are you getting good experience at this workplace or are you are always stuck doing the grunt work? If you are getting good experience, is it enough to justify working at that place?