Baby too tall for car seat, appt an hour away

So my son is 9.5 months and at 7 months he was 28 inches tall. His infant car seat says to not use if baby is over 29 inches. He has a wellness check-up tomorrow here in town so I'll know his exact length but I am pretty sure he's above 29 inches now, just based on clothing fit and what he can reach while standing.

Anyway, he has another appointment Monday to see an eye doctor and we'll be on the road for two hours total. I ordered a new convertible seat for him last week and paid extra for rush shipping so it'd be here in time. I would have ordered it much sooner but my husband wanted to sell stuff first to make up for the cost and that delayed everything. -sigh- So today is the day the seat was supposed to be here and the order says it hasn't even shipped yet. Maybe it's just not been updated but I am worried it won't show up by tomorrow. (We leave at 7:45 AM Monday so it has to come by tomorrow for us to use it)

So what do I do? Reschedule the appointment or use the seat anyway if he's too tall? My husband thinks it'll be fine but I really don't like the idea. ):

Quoting emmygog[Felix's Mommy]:" So my son is 9.5 months and at 7 months he was 28 inches tall. His infant car seat says to not use if ... [snip!] ... the appointment or use the seat anyway if he's too tall? My husband thinks it'll be fine but I really don't like the idea. ):"

im assuming he is in an infant Carrier?
is his head still beneath the outer shell?

What seat is he in now & does he have more than 1" of room from the top of his head to top of shell?

You can see how to measure that 1" here:
http://www.car-seat.org/showthread.php?t=30201

I can only measure in the house as my husband has our car right now but it's right at one inch. That link says there'd be even less space if he was sitting less upright so...I assume that probably means there is less than one inch, right? ):

If his head sticks over then reschedule the appointment

<blockquote><b>Quoting applelove:</b>" If his head sticks over then reschedule the appointment "</blockquote>

Probably going to have to do that. ): Worst part is that it took us two months to get this appointment and I'm sure they'll make us wait that long again. The only other option I can think of is to buy another seat available in town (none of which are great...) and use that. Then we'd have two seats, though, and I don't know if I'm allowed to return one after using it... Probably not. ): Ugh. Wish we had ordered it sooner. ):

You could get a cheap $50 convertible like the Cosco Apt & use it as a backup, in case kiddo ever rides with someone else. Would last till at least 2 RF.

Id buy a cheap cosco carseat from walmart to use and if my husband had anything to say about it id tell him to quit his griping because i said we needed to order the carseat sooner.

Welp, I got a hold of Walmart and it turns out they never shipped it because it's not in stock. :/ I wonder why I was allowed to order it and why they didn't inform me my order would not arrive on time. Ugh. Thankfully I was allowed to cancel the order and get a refund. I am going to Target in the morning to buy a similar seat that appears to be in stock. Hopefully the site is correct. I've had it tell me something was in stock just to have an employee claim they'd never even seen or heard of it. ;P Either way, I saw at least a few potentially good seats so we're getting SOMETHING no matter what!