We have used Gwald for years and specifically because of the Sunshine creche at the top of mannlichen. We certainly put our first child in there from age 8 months and second one (as usual) even earlier) - we have seen really small babies inthere which seems a little tough but it is poss. It has recently changed hands but they run on same lines (7 days a week) They take babies and upwards. Moreover I am pretty sure that if queue at bottom is bad they let you and your family skip around the side - you just ask at Kiosk to right of caisse. They used to pick up and drop off at your hotel but you would need to ask given now run by swiss ski school.
Oddly the ski school that operate at top of Mannlichen dont operate the creche but they will still happily arrange to pick up drop off at creche if your kids cant do a whole day of either skiing/creche.
Also swiss ski school will take from 6 months at Bodmi area but only on fridays and it pretty much means you have to ski first side.
Check it all out on the grindelwaldsports website or tourism site