I am curious what people consider adequate play time for a kitten?
Depends on the kitten. I have 4 SVs -- an F1, 2 F2s and an F6. The F1 and F6 want to play ALL day EVERY day with me. We have about 100 toys here -- balls, jingly things, things that squeak, puzzle toys that I can hide treats in to keep them busy. Doesn't matter one bit. They want to play with me -- fetch for hours on end or chasing a feather wand or hide and seek.... The F2s like to play for 30 minutes at a time several times throughout the day. They all love to rock and roll between midnight and 5 a.m.
All of mine are grown now. The F1 will be 3 in February the others are 7-8 yrs. When they were kittens, their play needs were far greater than they are now (with the exception of the F1 & F6). The energy of most SVs when they're babies is unbelievable -- it has to be seen to be believed. They play hard, sleep, play hard, sleep at about half hour intervals. While they're sleeping, they're growing. The first year is usually the hardest when they need lots of human interaction and play. When they hit the 2nd year, they slow down a bit and by the third year they are almost civilized
All of mine (with the exception of the F1 who is a legend unto himself) followed the same pattern -- lots of play and not much snuggling the first year or two. At the end of their 2nd year and definitely by the end of their 3rd year they were major snugglers -- demanding lap time, kisses, hugs. The F1 has been a velcro cat from the beginning. If I'm out of his sight for 5 minutes he acts like his world is coming to an end.
It's been mentioned earlier in this thread that you'll need to make time to play with the kitten before you leave the house in the morning and for the first hour or two when you come home after work. There will be changes that you may need to make in your life. You may have to give up some of your human leisure time for cat time. There is one thing that is universally true for all savannahs -- all owners have had to adapt their lives to the cats, the cats are limited in how they'll adapt to your life. So if you aren't prepared or willing to make sacrifices to keep the cat happy and healthy, don't get one until you are ready to make sacrifices.