This is what Bobby says before they burn him -

Here's to... running into you guys on the other side. Only... not too soon. All right?

I took this to be a 'well, we don't know what's going to happen to me, but hopefully I'll go Up and I'll see you there later.' That's why there's a 'here's to...' - meaning 'here's hoping...'

I don't think there's enough certainty about it for them to have known for sure, or been saying for sure, that Bobby was definitely going to Heaven.

*shrug*