I don't where this rumour originated, but I certainly haven't heard anything like this (and I deal with both the SQ and the DP 1 Inf).
What's taught on the SQ is not taught on the DP 1 Inf and whomever is telling you that needs to pull their head out of their anal orifice.
C9 and C6 are both taught during the SQ and are not repeated during the DP 1 Inf. A couple of topics appear during both courses, such as patrolling, but the SQ provides a brief introduction to the material while the DP 1 Inf goes into considerably more detail.
Besides from an over abundance of controlled substances, I can see two possbile origins of this rumour, although the perpetrators would have to have taken things totally out of context:
1. The SQ will disappear for all trades (not just Inf) in a year or so once the Enhanced BMQ course is finalized. However, there will not be a difference in what the student does, the material will just appear during a different course.
2. Someone may be getting confused over the policy for out of sequence training. However the circumstances during which this is allowed to occur are quite specific and seldom (if ever) apply to unit run training.