I've seen the other 2 responses, & I believe that would be way underpaid considering the cost of gas today, not to mention your time. I would figure out the cost of gas per round trip, & then figure out what its worth after that. I know I have a dog, & after gas expenses I would think I should pay $20 a visit or if twice a day then a daily total of $30 before gas. You have a 9 month old & your time is valuable. You may end up regretting taking on this responsibility if you do it for less than it's worth.
That's my opinion.